First-principles study of back-contact effects on CdTe thin-film solar cells
Mao-Hua Du
Forming a chemically stable low-resistance back contact for CdTe thin-film solar cells is critically important to the cell performance. This paper reports theoretical study of the effects of the back-contact material, SbTe, on the performance of the CdTe solar cells. First-principles calculations sh ... [Phys. Rev. B 80, 205322 (2009)] published Fri Nov 20, 2009.
Switching the electric and magnetic responses in a metamaterial
Xiang Xiong, Wei-Hua Sun, Yong-Jun Bao, Ru-Wen Peng, Mu Wang et al.
We demonstrate in this Rapid Communication that in an assembly of stacked metallic U-shaped resonators, pure magnetic and electric responses are, respectively, realized, and the magnetic and electric responses can be switched at the same frequency by changing the polarization of incident light for 9 ... [Phys. Rev. B 80, 201105 (2009)] published Fri Nov 20, 2009.
Interaction effects in the optical conductivity of bilayer graphene: Drude-interband coupling and screening
Wang-Kong Tse and A. H. MacDonald
We present a theory of the influence of band renormalization and excitonic electron-electron interaction effects on the optical conductivity sigma(omega) of doped bilayer graphene. Using the Keldysh formalism, we derive a kinetic equation from which we extract numerical and approximate analytic resu ... [Phys. Rev. B 80, 195418 (2009)] published Fri Nov 20, 2009.
Pressure tuning of the thermal conductivity of the layered muscovite crystal
Wen-Pin Hsieh, Bin Chen, Jie Li, Pawel Keblinski, and David G. Cahill
The physics of heat conduction in layered, anisotropic crystals is probed by measurements of the cross-plane elastic constant C and thermal conductivity Lambda of muscovite mica as a function of hydrostatic pressure. Picosecond interferometry and time-domain thermoreflectance provide high-precision ... [Phys. Rev. B 80, 180302 (2009)] published Fri Nov 20, 2009.
Accurate Hartree-Fock energy of extended systems using large Gaussian basis sets
Joachim Paier, Cristian V. Diaconu, Gustavo E. Scuseria, Manuel Guidon, Joost VandeVondele et al.
Calculating highly accurate thermochemical properties of condensed matter via wave-function-based approaches (such as, e.g., Hartree-Fock or hybrid functionals) has recently attracted much interest. We here present two strategies providing accurate Hartree-Fock energies for solid LiH in a large Gaus ... [Phys. Rev. B 80, 174114 (2009)] published Fri Nov 20, 2009.
Tunable Red Luminescence of Mn-Doped NaCaPO Phosphors
Suyin Zhang, Yanlin Huang, Weifang Kai, Liang Shi, and Hyo Jin Seo
Mn-doped NaCaPO were synthesized by a solid-state reaction. The structure and luminescence were investigated. The main excitation bands located at a band extending from 380 to 450 nm could match the emission of UV light emitting diode chips. The phosphors exhibited the emission in the wavelength ran ... [Electrochem. Solid-State Lett. 13, J11 (2009)] published Fri Nov 20, 2009.
Self-Sustained Levitation of Dust Aggregate Ensembles by Temperature-Gradient-Induced Overpressures
Thorben Kelling and Gerhard Wurm
In laboratory experiments we observe dust aggregates from 100 [mu]m to 1 cm in size composed of micrometer-sized grains levitating over a hot surface. Depending on the dust sample aggregates start to levitate at a temperature of 400 K. Levitation of dust aggregates is restricted to a pressure range ... [Phys. Rev. Lett. 103, 215502 (2009)] published Fri Nov 20, 2009.
Creating Polarization-Entangled Photon Pairs from a Semiconductor Quantum Dot Using the Optical Stark Effect
Andreas Muller, Wei Fang, John Lawall, and Glenn S. Solomon
In typical epitaxial quantum dots (QDs) the ideally degenerate optical excitons are energy split, preventing the formation of two-photon entanglement in a biexciton decay. We use an external field, here a continuous-wave laser tuned to the QD in the ac Stark limit, to cancel the splitting and create ... [Phys. Rev. Lett. 103, 217402 (2009)] published Fri Nov 20, 2009.
Diffractions of Elastic Waves and Stress Concentration Near a Cylindrical Nano-Inclusion Incorporating Surface Effect
Y. Ru, G. F. Wang, and T. J. Wang
The diffractions of plane compressional waves (P-wave) and shear waves (SV-wave) by a cylindrical nano-inclusion are investigated in this paper. To account for the surface/interface effect at nanoscale, the surface/interface elasticity theory is adopted in the analysis. Using the displacement potent ... [J. Vib. Acoust. 131, 061011 (2009)] published Fri Nov 20, 2009.
Photoelectron spectroscopy study of systematically varied doping concentrations in an organic semiconductor layer using a molecular p-dopant
S. Olthof, W. Tress, R. Meerheim, B. Lussem, and K. Leo
We investigate the doping behavior of the strongly electron accepting molecule 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane coevaporated with the host molecule N,N,N,N-tetrakis(4-methoxyphenyl)-benzidine by photoemission spectroscopy and conductivity measurements. Using interface resolved me ... [J. Appl. Phys. 106, 103711 (2009)] published Fri Nov 20, 2009.
Optical spectroscopy and upconversion luminescence in Nd doped GaGeS glass
Vineet Kumar Rai, Cid B. de Araujo, Y. Ledemi, B. Bureau, M. Poulain et al.
Optical properties of a neodymium (Nd) doped glass having composition based on the (GaS)(GeS) system are reported. Transition probabilities, radiative lifetimes, and branching ratios related to Nd levels were determined. Frequency upconversion (UC) luminescence due to nonresonant excitation at 1064 ... [J. Appl. Phys. 106, 103512 (2009)] published Fri Nov 20, 2009.
Short- and long-range orders in FeCr: A Monte Carlo study
C. Pareige, C. Domain, and P. Olsson
Atomistic kinetic Monte Carlo simulations based on the two-band semiempirical cohesive model for FeCr have revealed a body centered tetragonal FeCr ordered compound at very low temperatures. Density functional theory calculations have shown that this structure is more stable than the FeCr compound r ... [J. Appl. Phys. 106, 104906 (2009)] published Fri Nov 20, 2009.
Enhancement of phosphorus activation in vacancy engineered thin silicon-on-insulator substrates
A. J. Smith, R. M. Gwilliam, V. Stolojan, A. P. Knights, P. G. Coleman et al.
The concentration of vacancy-type defects in a silicon-on-insulator substrate consisting of a 110 nm silicon overlayer and a 200 nm buried oxide has been quantified using variable energy positron annihilation spectroscopy following 300 keV Si ion implantation to a dose of 1.5 x 10 cm and subsequent ... [J. Appl. Phys. 106, 103514 (2009)] published Fri Nov 20, 2009.
Thermal stability and vibrational spectroscopy of NO shallow donor centers in silicon
Hans Christian Alt and Hans Edwin Wagner
NO-related shallow donors in nitrogen-doped Czochralski silicon have been studied by infrared spectroscopy. Quasithermal equilibrium states were established by long-term thermal annealing in the temperature range from 600 to 1000 degrees C. By quantitative analysis of the 1s-->2p far-infrared el ... [J. Appl. Phys. 106, 103511 (2009)] published Fri Nov 20, 2009.
Nanocrystalline cobalt-based films with high thermal stability from a single molecule
Lucas B. Henderson, Joseph H. Rivers, Daniel E. Bost, Richard A. Jones, and John G. Ekerdt
Thin nanocrystalline hcp Co-based films are grown by chemical vapor deposition on SiO. Tetrakis(trimethylphosphine)cobalt(0), ((CH)P)Co, is a single-source precursor that forms Co films that incorporate both P and C when the substrate temperature ranges from 225 to 325 degrees C, and feature crysta ... [J. Vac. Sci. Technol. A 28, 54 (2009)] published Fri Nov 20, 2009.
Crystal Structure, Oxygen Nonstoichiometry, and Conductivity of Mixed IonicElectronic Conducting Perovskite Composites with CeO
E. Konysheva, S. M. Francis, and J. T. S. Irvine
Conductivity, structure, and oxygen nonstoichiometry of compositions in the following series (100x) LaSrCoOxCeO (LSCCe) and (100x) LaSrMnOxCeO (LSMCe), where x=0, 2, 5, and 10 mol %, are studied. CeO has a low solubility limit in the rhombohedral structure. Compositions containing more than 2 mol ... [J. Electrochem. Soc. 157, B159 (2009)] published Thu Nov 19, 2009.
Picosecond ultrasonic measurements of attenuation of longitudinal acoustic phonons in silicon
B. C. Daly, K. Kang, Y. Wang, and David G. Cahill
We report ultrafast optical measurements of the attenuation of 50 and 100 GHz longitudinal acoustic-phonon pulses in Si. Picosecond acoustic measurements were made at temperatures 50
Devil's staircases and supersolids in a one-dimensional dipolar Bose gas
F. J. Burnell, Meera M. Parish, N. R. Cooper, and S. L. Sondhi
We consider a single-component gas of dipolar bosons confined in a one-dimensional optical lattice, where the dipoles are aligned such that the long-ranged dipolar interactions are maximally repulsive. In the limit of zero intersite hopping and sufficiently large on-site interaction, the phase diagr ... [Phys. Rev. B 80, 174519 (2009)] published Thu Nov 19, 2009.
Nucleation and first-stage growth processes of extrinsic defects in GaAs triggered by self-interstitials
F. Gala and G. Zollo
The growth process of small self-interstitial clusters I (n<=7) in crystalline GaAs has been addressed by semi-empirical tight-binding molecular-dynamics technique. The I ground-state structures have been found among many possible choices of topological properties and stoichiometric compositions. Th ... [Phys. Rev. B 80, 174113 (2009)] published Thu Nov 19, 2009.
High-pressure Raman and x-ray diffraction studies on LaB
B. K. Godwal, E. A. Petruska, S. Speziale, J. Yan, S. M. Clark et al.
X-ray diffraction measurements and Raman spectroscopy at room temperature document the equation of state and the frequency shifts for E, T, and A vibrational modes of polycrystalline LaB under pressure. The data exhibit smooth pressure dependencies, yielding a zero-pressure isothermal bulk modulus K ... [Phys. Rev. B 80, 172104 (2009)] published Thu Nov 19, 2009.
Stopping of energetic cobalt clusters and formation of radiation damage in graphite
Vladimir N. Popok, Sasa VuCkovic, Juha Samela, Tommi T. Jarvi, Kai Nordlund et al.
The interaction of energetic (up to 200 eV/atom) size-selected Co clusters with HOPG is studied both experimentally and theoretically. Etching of the radiation damaged areas introduced by cluster impacts provides a measure of the depth to which the collision cascades are developed and allows a compa ... [Phys. Rev. B 80, 205419 (2009)] published Thu Nov 19, 2009.
Cooperative mechanism for anchoring highly polar molecules at an ionic surface
J. Schutte, R. Bechstein, M. Rohlfing, M. Reichling, and A. Kuhnle
Structure formation of the highly polar molecule cytosine on the (111) cleavage plane of calcium fluoride is investigated in ultrahigh vacuum using noncontact atomic force microscopy at room temperature. Molecules form well-defined trimer structures, covering the surface as homogeneously distributed ... [Phys. Rev. B 80, 205421 (2009)] published Thu Nov 19, 2009.
Quantum confinement and thermal effects on the Raman spectra of Si nanocrystals
Giuseppe Faraci, Santo Gibilisco, and Agata R. Pennisi
In nanocrystals, first-order Raman spectra can exhibit large shift and width due to two overlapping effects: quantum confinement and thermal heating. In order to distinguish each contribution we studied silicon nanocrystals by Raman spectroscopy. From the measurements we extracted the dependence of ... [Phys. Rev. B 80, 193410 (2009)] published Thu Nov 19, 2009.
Low-temperature observation of the softened C-H stretching vibrations of cyclohexane on Rh(111)
Takanori Koitaya, Atsushi Beniya, Kozo Mukai, Shinya Yoshimoto, and Jun Yoshinobu
The C-H stretching vibrations of cyclohexane on Rh(111) were investigated using infrared reflection absorption spectroscopy between 20 and 89 K. At 20 K, the softened C-H stretching band consists of several sharp peaks, ranging from 2500 to 2700 cm. The wide-range distribution of the softened C-H s ... [Phys. Rev. B 80, 193409 (2009)] published Thu Nov 19, 2009.
Stabilization of large silicon fullerenes and related nanostructures through puckering and poly(oligo)merization
Aristides D. Zdetsis
The structure, symmetry, and stability of large SiH, n=60, 70, 76, 80, and 180 cages and the SiH ligomers: SiH, SiH, and SiH, together with some related fullerenes and nanostructures, are studied by ab initio density functional theory and second order Moller-Plesset perturbation theory (for SiH). It ... [Phys. Rev. B 80, 195417 (2009)] published Thu Nov 19, 2009.
Phonon density of states and heat capacity of LaTe
O. Delaire, A. F. May, M. A. McGuire, W. D. Porter, M. S. Lucas et al.
The phonon density of states (DOS) of LaTe compounds (x=0.0,0.18,0.32) was measured at 300, 520, and 780 K, using inelastic neutron scattering. A significant stiffening of the phonon DOS and a large broadening of features were observed upon introduction of vacancies on La sites (increasing x). Heat- ... [Phys. Rev. B 80, 184302 (2009)] published Thu Nov 19, 2009.
Extension of the RosencwaigGershoFernelius photothermal deflection spectroscopy model to account for multiple reflections in epitaxial samples
I. C. W. Chan and M. Beaudoin
The Fernelius extension to the RosencwaigGersho theory for photothermal deflection spectroscopy (PDS) is modified to take into account multiple reflections and light trapping within a thin film-on-substrate system where both the thin film and the substrate can be absorbing. The extended model is use ... [J. Appl. Phys. 106, 103510 (2009)] published Thu Nov 19, 2009.
The Debye-like relaxation mechanism in poly(vinylidene fluoride-trifluoroethylene) ferroelectric polymers
P. F. Liu, P. Gemeiner, X. J. Meng, J. H. Chu, S. Geiger et al.
In this work we studied 65-nm-thick poly(vinylidene fluoride-trifluoroethylene) ferroelectric polymers films grown by LangmuirBlodgett onto silicon substrates. Three dielectric anomalies have been unambiguously evidenced. The high temperature one near 380 K corresponds to the ferroelectric-paraelect ... [J. Appl. Phys. 106, 104113 (2009)] published Thu Nov 19, 2009.
Computational study of thermocompression bonding of carbon nanotubes to metallic substrates
Xiaohui Song, Zhiyin Gan, Sheng Liu, Han Yan, and Qiang Lv
Thermocompression bonding of carbon nanotubes (CNTs) to metallic substrates is studied using molecular dynamics. The interaction of the CNT and the metal cluster at high temperature is investigated first. For the diffusion bonding process, the effects of temperature and external pressure are examine ... [J. Appl. Phys. 106, 104308 (2009)] published Thu Nov 19, 2009.
Adsorption of Ar on planar surfaces studied with a density functional theory
Salvador A. Sartarelli and Leszek Szybisz
The adsorption of Ar on planar structureless substrates of alkali metals, alkaline-earth metal Mg, CO, and Au was analyzed by applying a density functional formalism which includes a recently proposed effective attractive pair potential conditioned to Ar. It is shown that this approach reproduces th ... [Phys. Rev. E 80, 052602 (2009)] published Thu Nov 19, 2009.
A molecular dynamics study of the influence of ionic charge distribution on the dynamics of a molten salt
Hualin Li and Mark N. Kobrak
The distribution of charge in an ion of a fused salt is known to be an important determinant of liquid dynamics. However, the details of this relationship remain poorly understood. We present the results of molecular dynamics simulations on a model molten salt system and show that changes in the dis ... [J. Chem. Phys. 131, 194507 (2009)] published Thu Nov 19, 2009.
Swelling and collapse of polyelectrolyte gels in equilibrium with monovalent and divalent electrolyte solutions
De-Wei Yin, Monica Olvera de la Cruz, and Juan J. de Pablo
The swelling of polyelectrolyte (PE) gels by 1:1 and 2:1 salts is studied via osmotic ensemble Monte Carlo simulations at constant osmotic pressure and electrolyte chemical potential of a reservoir phase in equilibrium with a model PE network. Large molecular weight gels exhibit a remarkable swellin ... [J. Chem. Phys. 131, 194907 (2009)] published Thu Nov 19, 2009.
Localized soft modes and the supercooled liquid's irreversible passage through its configuration space
Asaph Widmer-Cooper, Heidi Perry, Peter Harrowell, and David R. Reichman
Using computer simulations, we show that the localized low frequency normal modes of a configuration in a supercooled liquid are strongly correlated with the irreversible structural reorganization of the particles within that configuration. Establishing this correlation constitutes the identificatio ... [J. Chem. Phys. 131, 194508 (2009)] published Thu Nov 19, 2009.
Publisher's Note: Transition state analysis of solid-solid transformations in nanocrystals [J. Chem. Phys. 131, 164116 (2009)]
Michael Grunwald and Christoph Dellago
Abstract not available. [J. Chem. Phys. 131, 199901 (2009)] published Thu Nov 19, 2009.
Dynamical and quasistatic structural relaxation paths in PdNiP glass
A. Kahl, T. Koeppe, D. Bedorf, R. Richert, M. L. Lind et al.
By sequential heat treatment of a PdNiP metallic glass at temperatures and durations for which alpha-relaxation is not possible, dynamic, and quasistatic relaxation paths below the glass transition are identified via ex situ ultrasonic measurements following each heat treatment. The dynamic relaxati ... [Appl. Phys. Lett. 95, 201903 (2009)] published Thu Nov 19, 2009.
Superhydrophobic floatability of a hydrophilic object driven by edge effect
Feng-Ming Chang, Yu-Jane Sheng, and Heng-Kwong Tsao
It is generally believed that a water-repellent surface is necessary for small insects to stand on water. Through a combined experimental and theoretical study, we demonstrate that an object with hydrophilic surface can float with apparent contact angle greater than 90 degrees due to edge effect. T ... [Appl. Phys. Lett. 95, 204107 (2009)] published Thu Nov 19, 2009.
Photoluminescence enhancement of Er-doped silica containing Ge nanoclusters
J. Guzman, S. J. Shin, C. Y. Liao, C. W. Yuan, P. R. Stone et al.
The photoluminescence (PL) of Er-doped silica films containing Ge nanoclusters synthesized by ion implantation was investigated. The area of the 1540 nm Er PL peak was enhanced by up to a factor of 200 by the addition of Ge nanoclusters. The PL enhancement was found to be proportional to the concent ... [Appl. Phys. Lett. 95, 201904 (2009)] published Thu Nov 19, 2009.
Inaccuracy of Density Functional Theory Calculations for Dihydrogen Binding Energetics onto Ca Cation Centers
Janghwan Cha, Seokho Lim, Cheol Ho Choi, Moon-Hyun Cha, and Noejung Park
We investigate the mechanism of dihydrogen adsorption onto Ca cation centers, which has been the significant focus of recent research for hydrogen storage. We particularly concentrate on reliability of commonly used density-functional theories, in comparison with correlated wave function theories. I ... [Phys. Rev. Lett. 103, 216102 (2009)] published Thu Nov 19, 2009.
Grain Growth Enhancement and Ga Distribution of Cu(InGa)Se Film Using CuSe Layer on CuInGa Metal Precursor
Min Sik Kim, R. B. V. Chalapathy, Kyung Hoon Yoon, and Byung Tae Ahn
A precursor layer for Cu(InGa)Se (CIGS) was deposited by simultaneous sputtering of CuIn and CuGa and subsequent sputtering of CuSe. The CuSe/metal alloy-stacked precursor was selenized at 550 degrees C in a Se vapor atmosphere to grow a CIGS film. The thickness of the CuSe layer was varied to contr ... [J. Electrochem. Soc. 157, B154 (2009)] published Wed Nov 18, 2009.
Extended excitons and compact heliumlike biexcitons in type-II quantum dots
Bhavtosh Bansal, S. Godefroo, M. Hayne, G. Medeiros-Ribeiro, and V. V. Moshchalkov
We have used magnetophotoluminescence measurements to establish that InP/GaAs quantum dots have a type-II (staggered) band alignment. The average excitonic Bohr radius and the binding energy are estimated to be 15 nm and 1.5 meV, respectively. When compared to bulk InP, the excitonic binding is weak ... [Phys. Rev. B 80, 205317 (2009)] published Wed Nov 18, 2009.
Antibonding plasmon mode coupling of an individual hole in a thin metallic film
J. W. Lee, T. H. Park, Peter Nordlander, and Daniel M. Mittleman
The polarization dependence of the optical properties of individual subwavelength holes in a thin metallic film is studied using terahertz time-domain spectroscopy. We show that for parallel polarization of the incident light, the coupling is predominantly to short-range bonding film plasmons while ... [Phys. Rev. B 80, 205417 (2009)] published Wed Nov 18, 2009.
Ultranarrow coupling-induced transparency bands in hybrid plasmonic systems
Thomas Zentgraf, Shuang Zhang, Rupert F. Oulton, and Xiang Zhang
Plasmons in nanoscale structures represent an exciting new route toward efficient manipulation of photons, especially at subwavelength scales. Of particular interest are the hybridized plasmonic systems, in which the interaction among the plasmonic elements can be utilized to tailor the optical resp ... [Phys. Rev. B 80, 195415 (2009)] published Wed Nov 18, 2009.
Changing the physical and chemical properties of titanium oxynitrides TiNO by changing the composition
Jesus Graciani, Said Hamad, and Javier Fdez. Sanz
The stability and structural properties of titanium oxynitrides, TiNO, of different compositions are theoretically analyzed by means of first-principles periodic density-functional calculations. We show that at x=0.550.6 there is a change in the preferred structure from that of NaCl type to the alph ... [Phys. Rev. B 80, 184112 (2009)] published Wed Nov 18, 2009.
3d transition metal impurities in aluminum: A first-principles study
M. Mantina, S. L. Shang, Y. Wang, L. Q. Chen, and Z. K. Liu
In this work, appropriate description of interactions of 3d transition metals in aluminum (Al-3d) is attained from first-principles using LDA+U potential within density-functional theory. By reproducing diffusion coefficients of 3d transition metals in aluminum in agreement with reliable data from e ... [Phys. Rev. B 80, 184111 (2009)] published Wed Nov 18, 2009.
Selection-rule blockade and rectification in quantum heat transport
Teemu Ojanen
We present a thermal transport phenomenon, a unidirectional selection-rule blockade, and show how it produces unprecedented rectification of bosonic heat flow through molecular or mesoscopic quantum systems. Rectification arises from the quantization of energy levels of the conduction element and se ... [Phys. Rev. B 80, 180301 (2009)] published Wed Nov 18, 2009.
Effects of methanol on nanoparticle self-assembly at liquid-liquid interfaces: A molecular dynamics approach
Mingxiang Luo, Yanmei Song, and Lenore L. Dai
Molecular dynamics simulations have been performed to study the influence of methanol on the self-assembly of nanoparticles at liquid-liquid interfaces. The simulation shows that the methanol molecules, at low volume fraction, stay in the aqueous phase but with a preference of the water-trichloroeth ... [J. Chem. Phys. 131, 194703 (2009)] published Wed Nov 18, 2009.
Extrinsic curvature, geometric optics, and lamellar order on curved substrates
Randall D. Kamien, David R. Nelson, Christian D. Santangelo, and Vincenzo Vitelli
When thermal energies are weak, two-dimensional lamellar structures confined on a curved substrate display complex patterns arising from the competition between layer bending and compression in the presence of geometric constraints. We present broad design principles to engineer the geometry of the ... [Phys. Rev. E 80, 051703 (2009)] published Wed Nov 18, 2009.
Visualization of highly graded oxygen vacancy profiles in lead-zirconate-titanate by spectrally resolved cathodoluminescence spectroscopy
Atsuo Matsutani, Zhenhua (Jerry) Luo, Soodkhet Pojprapai, Mark Hoffman, and Giuseppe Pezzotti
The ultraviolet and visible cathodoluminescence (CL) emitted at room temperature from bulk hard lead-zirconate-titanate polycrystalline perovskite has been systematically collected before and after an annealing cycle conducted in a reducing atmosphere. Spectroscopic assessments have been made of the ... [Appl. Phys. Lett. 95, 202903 (2009)] published Wed Nov 18, 2009.
Shape-dependent nonlinear absorption and relaxation in CuInS nanocrystals
N. Venkatram, Sudip K. Batabyal, Lu Tian, Jagadese J. Vittal, and Wei Ji
We report the observation of nonlinear-optical response and relaxation in copper indium sulfide (CuInS) crystalline nanoparticles and nanorods with femtosecond Z-scans and transient absorption measurements. Dependent on the size and shape, two-photon absorption and saturation in the one-photon absor ... [Appl. Phys. Lett. 95, 201109 (2009)] published Wed Nov 18, 2009.
Strength of lithium fluoride under shockless compression to 114 GPa
T. Ao, M. D. Knudson, J. R. Asay, and J.-P. Davis
A magnetic loading technique was used to ramp load single-crystal [100] lithium fluoride specimens to peak stresses of 5114 GPa. Wave analysis of in situ particle velocity profiles was used to estimate the compressive strength of LiF at peak stress. It was found that the strength increased with peak ... [J. Appl. Phys. 106, 103507 (2009)] published Wed Nov 18, 2009.
GeSbTe thin films deposited by pulsed laser: An ellipsometry and Raman scattering spectroscopy study
P. Nemec, A. Moreac, V. Nazabal, M. Pavlista, J. Prikryl et al.
Pulsed laser (532 nm) deposited GeSbTe thin films were investigated by means of spectroscopic ellipsometry and Raman scattering spectroscopy. TaucLorentz and CodyLorentz models were employed for the evaluation of optical functions of thin films in as-deposited (amorphous) and crystalline (cubic) pha ... [J. Appl. Phys. 106, 103509 (2009)] published Wed Nov 18, 2009.
Enhancement of light transmission by coupling to surface plasmon polaritons of a layer-plus-islands silver layer
Pangpang Wang, Dongyan Zhang, Dong Hun Kim, Zhiyong Qiu, Lumei Gao et al.
Enhanced light transmission through coupling incident light with surface plasmon polaritons (SPPs) on a layer-plus-islands nanostructure Ag layer, surrounded by symmetric ZnO dielectrics (ZnO/Ag/ZnO), was investigated. The couple and decouple processes at ZnO/Ag and Ag/ZnO grating interfaces were co ... [J. Appl. Phys. 106, 103104 (2009)] published Wed Nov 18, 2009.
Energy transfer rates and population inversion of I excited state of Er investigated by means of numerical solutions of the rate equations system in Er:LiYF crystal
Laercio Gomes, Andre Felipe Henriques Librantz, Fabio Henrique Jagosich, Wonder Alexandre Luz Alves, Izilda Marcia Ranieri et al.
In this work, we present the spectroscopic properties of LiYF (YLF) single crystals activated by high doping of erbium ions. The most important processes that lead to the up-conversion erbium emissions in the infrared region were identified. A time-resolved luminescence spectroscopy technique was em ... [J. Appl. Phys. 106, 103508 (2009)] published Wed Nov 18, 2009.
Influence of annealing and Ag doping on structural and optical properties of indium tin oxide thin films
Chun-Bin Cao, Lei Xiao, Xue-Ping Song, and Zhao-Qi Sun
Indium tin oxide (ITO) and Ag (1.20.1 at. %)-ITO films with the thickness of 130 nm were deposited on glass substrates at room temperature by dc magnetron sputtering and postannealed at the temperature range of 200400 degrees C. By calculating the x-ray diffraction data, the lattice constants o ... [J. Vac. Sci. Technol. A 28, 48 (2009)] published Wed Nov 18, 2009.
A Quasidependent Scattering Radiative Properties Model for High Density Fiber Composites
Siu-Chun Lee
This paper presents a theoretical model for the radiative properties of fiber composites fabricated of spatially oriented fiber strands that contain closely spaced fibers in the Mie scattering regime. Dependent scattering within the dense fiber strands is accounted for by utilizing the solution of M ... [J. Heat Transfer 132, 021008 (2009)] published Wed Nov 18, 2009.
Near-Field Radiation Calculated With an Improved Dielectric Function Model for Doped Silicon
S. Basu, B. J. Lee, and Z. M. Zhang
This paper describes a theoretical investigation of near-field radiative heat transfer between doped silicon surfaces separated by a vacuum gap. An improved dielectric function model for heavily doped silicon is employed. The effects of doping level, polarization, and vacuum gap width on the spectra ... [J. Heat Transfer 132, 021005 (2009)] published Wed Nov 18, 2009.
Bose-Einstein Condensation in Quantum Glasses
Giuseppe Carleo, Marco Tarzia, and Francesco Zamponi
The role of geometrical frustration in strongly interacting bosonic systems is studied with a combined numerical and analytical approach. We demonstrate the existence of a novel quantum phase featuring both Bose-Einstein condensation and spin-glass behavior. The differences between such a phase and ... [Phys. Rev. Lett. 103, 215302 (2009)] published Wed Nov 18, 2009.
Adams and Olmsted Reply:
J. M. Adams and P. D. Olmsted
A Reply to the Comment by Shi-Qing Wang. ... [Phys. Rev. Lett. 103, 219802 (2009)] published Wed Nov 18, 2009.
Comment on Nonmonotonic Models are Not Necessary to Obtain Shear Banding Phenomena in Entangled Polymer Solutions
Shi-Qing Wang
A Comment on the Letter by J. M. Adams and P. D. Olmsted, Phys. Rev. Lett. 102, 067801 (2009). The authors of the Letter offer a Reply. ... [Phys. Rev. Lett. 103, 219801 (2009)] published Wed Nov 18, 2009.
Spin mapping at the nanoscale and atomic scale
Roland Wiesendanger
The direct observation of spin structures with atomic-scale resolution, a long-time dream in condensed matter research, recently became a reality based on the development of spin-sensitive scanning probe methods, such as spin-polarized scanning-tunneling microscopy (SP-STM) and magnetic exchange for ... [Rev. Mod. Phys. 81, 1495 (2009)] published Wed Nov 18, 2009.
Subpicosecond coherent nonlinear optical response of isolated single-walled carbon nanotubes
S. Tao, Y. Miyata, K. Yanagi, H. Kataura, and H. Okamoto
We report an excitation-energy dependence of ultrafast changes of exciton absorptions in isolated semiconducting single-walled carbon nanotubes. For a photoexcitation far below the exciton transition, a blueshift of exciton absorptions originating from the optical Stark effect due to exciton-photon ... [Phys. Rev. B 80, 201405 (2009)] published Tue Nov 17, 2009.
Azobenzene at coinage metal surfaces: Role of dispersive van der Waals interactions
Erik R. McNellis, Jorg Meyer, and Karsten Reuter
We use different semiempirical dispersion correction schemes to assess the role of long-range van der Waals interactions in the adsorption of the prototypical molecular switch azobenzene (CH-N-CH) at the coinage metal surfaces Cu(111), Ag(111), and Au(111). Compared to preceding density-functional t ... [Phys. Rev. B 80, 205414 (2009)] published Tue Nov 17, 2009.
Atomic nature of the Si-B4 paramagnetic center assessed by multifrequency electron spin resonance
K. Keunen and A. Stesmans
An electron spin resonance (ESR) study has been carried out in the range 4.2120 K on the trigonal Si-B4 center in annealed (200350 degrees C) neutron-irradiated p-type Si. Detailed observations reveal a rich Si hyperfine (hf) structure, indicating interaction of the unpaired electron with up to fiv ... [Phys. Rev. B 80, 195207 (2009)] published Tue Nov 17, 2009.
Temperature dependence of the electronic structure of the J=(1/2) Mott insulator SrIrO studied by optical spectroscopy
S. J. Moon, Hosub Jin, W. S. Choi, J. S. Lee, S. S. A. Seo et al.
We investigated the temperature-dependent evolution of the electronic structure of the J=(1/2) Mott insulator SrIrO using optical spectroscopy. The optical conductivity spectra sigma(omega) of this compound has recently been found to exhibit two d-d transitions associated with the transition between ... [Phys. Rev. B 80, 195110 (2009)] published Tue Nov 17, 2009.
Gradient elasticity and flexural wave dispersion in carbon nanotubes
Harm Askes and Elias C. Aifantis
Higher-order elasticity theories have recently been used to predict the dispersion characteristics of flexural waves in carbon nanotubes (CNTs). In particular, nonlocal elasticity and gradient elasticity (with unstable strain gradients) have been employed within the framework of classical Euler-Bern ... [Phys. Rev. B 80, 195412 (2009)] published Tue Nov 17, 2009.
Theory of dynamical scattering in near-edge electron energy loss spectroscopy
C. Witte, S. D. Findlay, M. P. Oxley, J. J. Rehr, and L. J. Allen
Beyond chemical information, the fine structure of an absorption edge gives bonding and electronic information. We provide a synthesis of fine structure and dynamical scattering theory, allowing the exploration of the effects of dynamical scattering on the measured fine structure. We discuss the eff ... [Phys. Rev. B 80, 184108 (2009)] published Tue Nov 17, 2009.
Driving-induced crossover in the avalanche criticality of martensitic transitions
Eduard Vives, Daniel Soto-Parra, Lluis Manosa, Ricardo Romero, and Antoni Planes
An experimental study of the statistical distribution of acoustic emission avalanches in martensitic transitions is presented. The critical exponents characterizing the power-law distributions of avalanches are measured as a function of cycling under soft-driving (stress-driving) and hard-driving (s ... [Phys. Rev. B 80, 180101 (2009)] published Tue Nov 17, 2009.
Phase diagram and critical behavior of the square-lattice Ising model with competing nearest-neighbor and next-nearest-neighbor interactions
Junqi Yin and D. P. Landau
Using the parallel tempering algorithm and graphics processing unit accelerated techniques, we have performed large-scale Monte Carlo simulations of the Ising model on a square lattice with antiferromagnetic (repulsive) nearest-neighbor and next-nearest-neighbor interactions of the same strength and ... [Phys. Rev. E 80, 051117 (2009)] published Tue Nov 17, 2009.
Large radiation fields from nonlocal interaction between terahertz waves and quantum wells with an applied electric field
Guanghui Wang and Qi Guo
The effects of pump intensities and applied electric fields on radiation fields excited by the nonlocal interaction between terahertz waves and AlGaAs/GaAs quantum wells (QWs) are investigated. The numerical results show the resonant radiation fields are very large in the confinement direction, and ... [J. Appl. Phys. 106, 103506 (2009)] published Tue Nov 17, 2009.
Scanning capacitance microscopy studies of unintentional doping in epitaxial lateral overgrowth GaN
J. Sumner, R. A. Oliver, M. J. Kappers, and C. J. Humphreys
Four samples were grown by epitaxial lateral overgrowth (ELOG) using different magnesium precursor fluxes during the coalescence stage. These samples were studied in cross section using scanning capacitance microscopy and scanning electron microscopy. The resulting images revealed the existence of s ... [J. Appl. Phys. 106, 104503 (2009)] published Tue Nov 17, 2009.
Study of acoustic wave behavior in silicon-based one-dimensional phononic-crystal plates using harmony response analysis
Xuefeng Zhu (祝雪丰), Tao Xu (徐涛), Shengchun Liu (刘盛春), and Jianchun Cheng (程建春)
We promote an efficient method named harmony response analysis (HRA) as a comparison with transient response analysis and supercell plane wave expansion (supercell PWE) to study the behavior of Lamb wave in silicon-based one-dimensional composite plates. To implement HRA for dealing with Lamb waves ... [J. Appl. Phys. 106, 104901 (2009)] published Tue Nov 17, 2009.
Vibration analysis of nanoplates under uniaxial prestressed conditions via nonlocal elasticity
T. Murmu and S. C. Pradhan
In this article, nonlocal elasticity theory is applied to investigate the vibration response of nanoplates under uniaxially prestressed conditions. Nonlocal elasticity theory takes into account the small-size effects when dealing with nanostructures. Nonlocal governing equations of the prestressed n ... [J. Appl. Phys. 106, 104301 (2009)] published Tue Nov 17, 2009.
SnO nanoparticles embedded in silica by ion implantation followed by thermal oxidation
M. A. Tagliente, V. Bello, G. Pellegrini, G. Mattei, P. Mazzoldi et al.
Nanoparticles of tin dioxide embedded in silica matrix were synthesized by ion implanting a Sn ion beam in a silica slide and by annealing in oxidizing atmosphere at 800 degrees C. A detailed structural and optical characterization was performed by using glancing incidence x-ray diffraction, transm ... [J. Appl. Phys. 106, 104304 (2009)] published Tue Nov 17, 2009.
Pressure-induced spin reorientation in LaSr(MnRu)O (y=0 and 0.075) single crystals
K. Mydeen, S. Arumugam, P. Mandal, A. Murugeswari, C. Sekar et al.
The effect of hydrostatic pressure (P) and external magnetic field on the c-axis resistivity (rho) and in-plane ac susceptibility (chi) of LaSr(MnRu)O (y=0 and 0.075) single crystals have been investigated. The ferromagnetic transition temperature (T) increases, while the conductivity decreases, wit ... [J. Appl. Phys. 106, 103908 (2009)] published Tue Nov 17, 2009.
Light absorption in silicon quantum dots embedded in silica
S. Mirabella, R. Agosta, G. Franzo, I. Crupi, M. Miritello et al.
The photon absorption in Si quantum dots (QDs) embedded in SiO has been systematically investigated by varying several parameters of the QD synthesis. Plasma-enhanced chemical vapor deposition (PECVD) or magnetron cosputtering (MS) have been used to deposit, upon quartz substrates, single layer, or ... [J. Appl. Phys. 106, 103505 (2009)] published Tue Nov 17, 2009.
Origin of translocation barriers for polyelectrolyte chains
Rajeev Kumar and M. Muthukumar
For single-file translocations of a charged macromolecule through a narrow pore, the crucial step of arrival of an end at the pore suffers from free energy barriers, arising from changes in intrachain electrostatic interaction, distribution of ionic clouds and solvent molecules, and conformational e ... [J. Chem. Phys. 131, 194903 (2009)] published Tue Nov 17, 2009.
Fluorescence depolarization in poly[2-methoxy-5-((2-ethylhexyl)oxy)-1,4-phenylenevinylene]: Sites versus eigenstates hopping
Jaykrishna Singh, Eric R. Bittner, David Beljonne, and Gregory D. Scholes
We report upon a theoretical study of singlet exciton migration and relaxation within a model conjugated polymer chain. Starting from poly[2-methoxy-5-((2-ethylhexyl)oxy)-1,4-phenylenevinylene] polymer chains, we assume that the pi-conjugation is disrupted by conformational disorder of the chain its ... [J. Chem. Phys. 131, 194905 (2009)] published Tue Nov 17, 2009.
Free energy landscape for the translocation of polymer through an interacting pore
Li-Zhen Sun, Wei-Ping Cao, and Meng-Bo Luo
Free energy landscapes for polymer chain translocating through an interacting pore are calculated by using exact enumeration method. A potential barrier exists at weak attractive or repulsive polymer-pore interaction and it changes to a potential well with the increase in the attraction. The result ... [J. Chem. Phys. 131, 194904 (2009)] published Tue Nov 17, 2009.
Stability of binary mixtures in electric field gradients
Sela Samin and Yoav Tsori
We consider the influence of electric field gradients on the phase behavior of nonpolar binary mixtures. Small fields give rise to smooth composition profiles, whereas large enough fields lead to a phase-separation transition. The critical field for demixing as well as the equilibrium phase-separati ... [J. Chem. Phys. 131, 194102 (2009)] published Tue Nov 17, 2009.
Measurement of anharmonicity of phonons in the negative thermal expansion compound Zn(CN) by high pressure inelastic neutron scattering
R. Mittal, S. L. Chaplot, and H. Schober
Zn(CN) is known to have an isotropic negative thermal expansion (NTE) coefficient (about 51 x 10 K) over 10370 K that is twice as large as that of ZrWO. We have measured the pressure dependence of the phonon spectra up to 30 meV from a polycrystalline sample of Zn(CN) at pressures of 0, 0.3, 1.9, a ... [Appl. Phys. Lett. 95, 201901 (2009)] published Mon Nov 16, 2009.
Calculated properties of fully hydrogenated single layers of BN, BCN, and graphene: Graphane and its BN-containing analogues
Frank W. Averill, James R. Morris, and Valentino R. Cooper
Carbon is an attractive material for hydrogen adsorption due to its light weight, variety of structures, and ability to both physisorb and chemisorb hydrogen. Recently, fully hydrogenated graphene layers (graphane) have been predicted to exist [J. O. Sofo et al., Phys. Rev. B 75, 15340 (2007)], and ... [Phys. Rev. B 80, 195411 (2009)] published Mon Nov 16, 2009.
Hydrogen diffusion in GaAsN
R. Trotta, D. Giubertoni, A. Polimeni, M. Bersani, M. Capizzi et al.
Hydrogen (or deuterium) incorporation in dilute nitride semiconductors modifies dramatically the electronic and structural properties of the crystal through the creation of nitrogen-hydrogen complexes. In this work, we investigate how the formation and dissociation of such complexes rule the diffusi ... [Phys. Rev. B 80, 195206 (2009)] published Mon Nov 16, 2009.
Pressure dependence of the large-scale structure of water
A. Cunsolo, F. Formisano, C. Ferrero, F. Bencivenga, and S. Finet
We report on small-angle x-ray scattering measurements on liquid water aimed at characterizing the pressure evolution of its large-scale structure. Diffraction profiles have been fitted assuming a Lorentzian dependence on the exchanged momentum. As a result, we observe an anomalous behavior of the d ... [J. Chem. Phys. 131, 194502 (2009)] published Mon Nov 16, 2009.
Numerical determination of the exponents controlling the relationship between time, length, and temperature in glass-forming liquids
Chiara Cammarota, Andrea Cavagna, Giacomo Gradenigo, Tomas S. Grigera, and Paolo Verrocchio
There is a certain consensus that the very fast growth of the relaxation time tau occurring in glass-forming liquids on lowering the temperature must be due to the thermally activated rearrangement of correlated regions of growing size. Even though measuring the size of these regions has defied scie ... [J. Chem. Phys. 131, 194901 (2009)] published Mon Nov 16, 2009.
Improvement of the ab initio embedded cluster method for luminescence properties of doped materials by taking into account impurity induced distortions: The example of YO:Bi
Florent Real, Belen Ordejon, Valerie Vallet, Jean-Pierre Flament, and Joel Schamps
New ab initio embedded-cluster calculations devoted to simulating the electronic spectroscopy of Bi impurities in YO sesquioxide for substitutions in either S or C cationic sites have been carried out taking special care of the quality of the environment. A considerable quantitative improvement with ... [J. Chem. Phys. 131, 194501 (2009)] published Mon Nov 16, 2009.
Theory for the three-dimensional Mercedes-Benz model of water
Alan Bizjak, Tomaz Urbic, Vojko Vlachy, and Ken A. Dill
The two-dimensional Mercedes-Benz (MB) model of water has been widely studied, both by Monte Carlo simulations and by integral equation methods. Here, we study the three-dimensional (3D) MB model. We treat water as spheres that interact through Lennard-Jones potentials and through a tetrahedral Gaus ... [J. Chem. Phys. 131, 194504 (2009)] published Mon Nov 16, 2009.
Ferroelectric order stability in the BiPbFeO solid solution
J. Chaigneau, R. Haumont, and J. M. Kiat
Ferroelectric properties of BiPbFeO, through a structural approach, by structural Rietveld refinement and x-ray diffraction versus temperature have been carried out. This study allows us to draw a phase diagram for the system BiPbFeO. Although lead atom gets a lone pair and is commonly understood as ... [Phys. Rev. B 80, 184107 (2009)] published Mon Nov 16, 2009.
Fast-ion conduction and flexibility and rigidity of solid electrolyte glasses
M. Micoulaut, M. Malki, D. I. Novita, and P. Boolchand
Electrical conductivity of dry, slow cooled (AgPO)(AgI) glasses is examined as a function of temperature, frequency, and glass composition. From these data compositional trends in activation energy for conductivity E(x), Coulomb energy E(x) for Ag ion creation, Kohlrausch stretched exponent beta(x), ... [Phys. Rev. B 80, 184205 (2009)] published Mon Nov 16, 2009.
Zero-point divacancy concentration in the shadow wave function model for solid He
R. Pessoa, M. de Koning, and S. A. Vitiello
We address the issue of interaction between zero-point vacancies in solid He as described within the shadow wave function model. Applying the reversible-work method and taking into account finite-size effects, we obtain a zero-point monovacancy concentration of (2.030.02) x 10, which is slightly hig ... [Phys. Rev. B 80, 172302 (2009)] published Mon Nov 16, 2009.
Effect of annealing on charge transfer in Ge nanocrystal based nonvolatile memory structure
M. Yang, T. P. Chen, Z. Liu, J. I. Wong, W. L. Zhang et al.
Ge nanocrystals (nc-Ge) embedded in the gate oxide of the nonvolatile memory structure were synthesized by Ge ion implantation followed by thermal annealing at 800 degrees C for various durations. Large changes in the structural and chemical properties of the Ge-implanted oxide have been observed, ... [J. Appl. Phys. 106, 103701 (2009)] published Mon Nov 16, 2009.
Extended x-ray absorption fine structure study of arsenic in HgCdTe: p-type doping linked to nonsubstitutional As incorporation in an unknown AsHg structure
X. Biquard, I. Alliot, and P. Ballet
An extended x-ray absorption fine structure (EXAFS) investigation has been carried out on arsenic-doped HgCdTe samples. The incorporation of atomic arsenic has been achieved using a nonconventional radio-frequency plasma source in a molecular beam epitaxy reactor. Two samples from the same epitaxial ... [J. Appl. Phys. 106, 103501 (2009)] published Mon Nov 16, 2009.
Near coalescent submicron polycrystalline diamond films deposited on silicon: Hydrogen bonding and thermal enhanced carbide formation
A. Stacey, Sh. Michaelson, J. Orwa, S. Rubanov, S. Prawer et al.
The influence of high temperature annealing up to 1200 degrees C in vacuum on ~100 nm nearly continuous thick diamond films consisting of 3050 nm crystallites, deposited onto silicon substrates is reported. The hydrogen bonding and phase composition of the films were studied with Raman spectroscop ... [J. Appl. Phys. 106, 103503 (2009)] published Mon Nov 16, 2009.
Angular Momentum Conservation for Coherently Manipulated Spin Polarization in Photoexcited NiO: An Ab Initio Calculation
Georgios Lefkidis, G. P. Zhang, and W. Hubner
In an ultrafast laser-induced magnetization-dynamics scenario we demonstrate for the first time an exact microscopic spin-switch mechanism. Combining ab initio electronic many-body theory and quantum optics analysis we show in detail how the coherently induced material polarization for every element ... [Phys. Rev. Lett. 103, 217401 (2009)] published Mon Nov 16, 2009.
Multiparticle Composites in Density-Imbalanced Quantum Fluids
Evgeni Burovski, Giuliano Orso, and Thierry Jolicoeur
We consider two-component one-dimensional quantum gases with a density imbalance. While generically such fluids are two-component Luttinger liquids, we show that if the ratio of the densities is a rational number, p/q, and mass asymmetry between components is sufficiently strong, one of the two eige ... [Phys. Rev. Lett. 103, 215301 (2009)] published Mon Nov 16, 2009.
Manifestation of Kohn Anomaly in 1/f Fluctuations in Metallic Carbon Nanotubes
Ju Hee Back, Cheng-Lin Tsai, Sunkook Kim, Saeed Mohammadi, and Moonsub Shim
Low-frequency noise in metallic single walled carbon nanotubes is shown to be strongly dependent on the Fermi level position and the applied electric field across the nanotube. Resonance-like enhancement observed near optical phonon energy only when the Fermi level lies near the Dirac point is corre ... [Phys. Rev. Lett. 103, 215501 (2009)] published Mon Nov 16, 2009.
Experimental realization of directed percolation criticality in turbulent liquid crystals
Kazumasa A. Takeuchi, Masafumi Kuroda, Hugues Chate, and Masaki Sano
This is a comprehensive report on the phase transition between two turbulent states of electroconvection in nematic liquid crystals, which was recently found by the authors to be in the directed percolation (DP) universality class [K. A. Takeuchi et al., Phys. Rev. Lett. 99, 234503 (2007)]. We furth ... [Phys. Rev. E 80, 051116 (2009)] published Mon Nov 16, 2009.
Valence-state transition in SrMnMoO (0<=x<=0.5) investigated by soft x-ray absorption spectroscopy
Jieun Lee, Bongjae Kim, B. H. Kim, B. I. Min, S. Kolesnik et al.
The electronic structures of perovskite SrMnMoO (0<=x<=0.5) have been investigated by employing soft x-ray absorption spectroscopy (XAS). Mn 2p XAS shows the systematic change in the valence states of Mn ions in SrMnMoO due to the substitution of hexavalent Mo(4d) ions. With increasing x, the valenc ... [Phys. Rev. B 80, 205112 (2009)] published Fri Nov 13, 2009.
Kondo screening cloud in the single-impurity Anderson model: A density matrix renormalization group study
Andreas Holzner, Ian P. McCulloch, Ulrich Schollwock, Jan von Delft, and Fabian Heidrich-Meisner
A magnetic moment in a metal or in a quantum dot is, at low temperatures, screened by the conduction electrons through the mechanism of the Kondo effect. This gives rise to spin-spin correlations between the magnetic moment and the conduction electrons, which can have a substantial spatial extension ... [Phys. Rev. B 80, 205114 (2009)] published Fri Nov 13, 2009.
Evolution of excess wing and beta-process in simple glass formers
Catalin Gainaru, Robert Kahlau, Ernst A. Rossler, and Roland Bohmer
Dielectric loss spectra of glass forming liquids are analyzed, with emphasis on systems for which a peak due to a secondary relaxation is not immediately obvious. Thus, glass formers are considered for which the high-frequency flank of the alpha-relaxation peak appears to be dominated by a so-called ... [J. Chem. Phys. 131, 184510 (2009)] published Fri Nov 13, 2009.
The thermodynamic and ground state properties of the TIP4P water octamer
E. Asare, A-R. Musah, E. Curotto, David L. Freeman, and J. D. Doll
Several stochastic simulations of the TIP4P [W. L. Jorgensen, J. Chandrasekhar, J. D. Madura, R. W. Impey, and M. L. Klein, J. Chem. Phys. 79, 926 (1983)] water octamer are performed. Use is made of the stereographic projection path integral and the Green's function stereographic projection diffusio ... [J. Chem. Phys. 131, 184508 (2009)] published Fri Nov 13, 2009.
Thermodynamic consistency of energy and virial routes: An exact proof within the linearized DebyeHuckel theory
Andres Santos, Riccardo Fantoni, and Achille Giacometti
The linearized DebyeHuckel theory for liquid state is shown to provide thermodynamically consistent virial and energy routes for any potential and for any dimensionality. The importance of this result for bounded potentials is discussed. ... [J. Chem. Phys. 131, 181105 (2009)] published Fri Nov 13, 2009.
Radiative lifetimes in undoped and p-doped InAs/GaAs quantum dots
Edmund Harbord, Peter Spencer, Edmund Clarke, and Ray Murray
We investigate the effect of p doping on the luminescence properties of InAs/GaAs self-assembled quantum dots (QDs). Continuous-wave and time-resolved photoluminescence measurements are obtained as a function of temperature and used to extract the radiative lifetime of the QD ground state. We find t ... [Phys. Rev. B 80, 195312 (2009)] published Fri Nov 13, 2009.
Electronic reconstruction at a buried ionic-covalent interface driven by surface reactions
C.-T. Lou (羅中廷), H.-D. Li (李宏道), J.-Y. Chung (鐘仁陽), D.-S. Lin (林登松), and T.-C. Chiang (江台章)
Lattice-matched ionic NaCl films were grown layer by layer on covalent Ge(100) using cycles of two half reactions (HRs) that involved the alternative adsorption of Cl and Na. The Ge 3d photoemission spectra obtained after full cycles of growth resembled that of clean Ge(100), but came to resemble th ... [Phys. Rev. B 80, 195311 (2009)] published Fri Nov 13, 2009.
Phase diagrams and isotopic effects of normal and deuterated water studied via x-ray diffraction up to 4.5 GPa and 500 K
G. Weck, J. Eggert, P. Loubeyre, N. Desbiens, E. Bourasseau et al.
We present synchrotron x-ray measurements in a diamond anvil cell of the molecular structure factor of HO and DO fluids up to 4.5 GPa and 500 K. We observe large changes in the structure factor and a dramatic increase in the oxygen coordination number over a 2 GPa pressure range. A P-T diagram of th ... [Phys. Rev. B 80, 180202 (2009)] published Fri Nov 13, 2009.
One-dimensional nanostructure-guided chain reactions: Harmonic and anharmonic interactions
Nitish Nair and Michael S. Strano
We have performed a parametric study of self-propagating chain reactions along a one-dimensional bead-spring array. The coupling between beads is modeled using harmonic and anharmonic Fermi-Pasta-Ulam (FPU)-beta and [cursive phi] potentials. The parameters that define the system are the activation e ... [Phys. Rev. B 80, 174301 (2009)] published Fri Nov 13, 2009.
Nuclear magnetic resonance study of Li implanted in a thin film of niobium
T. J. Parolin, J. Shi, Z. Salman, K. H. Chow, P. Dosanjh et al.
We report results of beta-detected NMR of Li implanted in Nb at high magnetic field. We identify two distinct sites for Li in the body-centered lattice. At low temperature, the site is characterized by a well-defined quadrupolar splitting. At about 50 K this site becomes unstable. Close to room temp ... [Phys. Rev. B 80, 174109 (2009)] published Fri Nov 13, 2009.
Giant changes in atomic dynamics on microalloying metallic melt
S. M. Chathoth, B. Damaschke, J. P. Embs, and K. Samwer
We report unexpectedly strong variations in the relaxational dynamics in a glass-forming metallic melt while microalloying. Analysis of quasielastic neutron scattering data revealed that changes in the values of stretching of the self-correlation function and the temperature dependence of self-diffu ... [Appl. Phys. Lett. 95, 191907 (2009)] published Fri Nov 13, 2009.
Robust atomic resolution imaging of light elements using scanning transmission electron microscopy
S. D. Findlay, N. Shibata, H. Sawada, E. Okunishi, Y. Kondo et al.
We show that an annular detector placed within the bright field cone in scanning transmission electron microscopy allows direct imaging of light elements in crystals. In contrast to common high angle annular dark field imaging, both light and heavy atom columns are visible simultaneously. In contras ... [Appl. Phys. Lett. 95, 191913 (2009)] published Fri Nov 13, 2009.
Silver half-shell arrays with controlled plasmonic response for fluorescence enhancement optimization
Cosmin Farcau and Simion Astilean
Regular arrays of interconnected silver half-shells (HSs) deposited on self-organized polystyrene microspheres are proposed as plasmonic substrates for metal-enhanced fluorescence. An emission enhancement of 28 times was demonstrated for Rose Bengal fluorophore placed at about 1 nm above HSs. The en ... [Appl. Phys. Lett. 95, 193110 (2009)] published Fri Nov 13, 2009.
Anharmonic phonon coupling in vapor-liquid-solid grown ZnO nanowires
A. Soudi, R. Lopez, Jr., R. D. Dawson, and Y. Gu
We have determined quantitatively third-order anharmonic phonon coupling matrix elements in vapor-liquid-solid (VLS) grown ZnO nanowires, via an analysis of the Raman line shape of the E phonon mode. The results suggest that the decay of the E phonon into the sum of two acoustic phonons is suppresse ... [Appl. Phys. Lett. 95, 193111 (2009)] published Fri Nov 13, 2009.
Transformation pathways in the solid-solid phase transitions of iron nanowires
Luis Sandoval and Herbert M. Urbassek
Using molecular dynamics simulations, we study the solid-solid phase transitions induced by strain in Fe nanowires. These show an intricate dependence on the crystallographic orientation of the wire. oriented nanowires exhibit a bcc-->fcc transition and preferably follow the NishiyamaWassermann pat ... [Appl. Phys. Lett. 95, 191909 (2009)] published Fri Nov 13, 2009.
Polarization splitting of discrete states in square shaped organic photonic dots
E. Siebert-Henze, M. Langner, M. Sudzius, S. I. Hintschich, H. Frob et al.
We analyze the polarization dependence of the discrete photonic states in an organic microcavity system that is laterally confined on the micron scale. Via microscopic photoluminescence measurements on square shaped photonic dots, we demonstrate a polarization splitting that increases up to 10 meV f ... [Appl. Phys. Lett. 95, 191116 (2009)] published Fri Nov 13, 2009.
Femtosecond carrier dynamics and saturable absorption in graphene suspensions
Sunil Kumar, M. Anija, N. Kamaraju, K. S. Vasu, K. S. Subrahmanyam et al.
Nonlinear optical properties and carrier relaxation dynamics in graphene, suspended in three different solvents, are investigated using femtosecond (80 fs pulses) Z-scan and degenerate pump-probe spectroscopy at 790 nm. The results demonstrate saturable absorption property of graphene with a nonline ... [Appl. Phys. Lett. 95, 191911 (2009)] published Fri Nov 13, 2009.
Organized Mesoporous TiO Films Stabilized by Phosphorus: Application for Dye-Sensitized Solar Cells
Marketa Zukalova, Jan Prochazka, Arnost Zukal, Jun Ho Yum, Ladislav Kavan et al.
A synthetic protocol was developed for the preparation of thin mesoporous TiO films with enhanced thermal stability. This objective was achieved by a modification of the procedure of supramolecular templating by a Pluronic P-123 copolymer by an addition of a small amount of phosphoric acid to the pr ... [J. Electrochem. Soc. 157, H99 (2009)] published Fri Nov 13, 2009.
Corrosion Behavior of Copper Thin Films in Organic HF-Containing Cleaning Solution for Semiconductor Applications
Nabil G. Mistkawi, Makarem A. Hussein, Malgorzata Ziomek-Moroz, and Shankar B. Rananavare
The corrosion behavior of electrochemically deposited copper thin films in deaerated and non-deaerated commercial cleaning solutions containing HF was investigated. Potentiodynamic polarization experiments were carried out to determine active, activepassive, passive, and transpassive regions. Corros ... [J. Electrochem. Soc. 157, C24 (2009)] published Fri Nov 13, 2009.