Mechanism of Na-doped p-type ZnO films: Suppressing Na interstitials by codoping with H and Na of appropriate concentrations
S. S. Lin, H. P. He, Y. F. Lu, and Z. Z. Ye
Hydrogen is codoped with sodium into ZnO films. X-ray photoelectron spectroscopy and secondary ion mass spectroscopy indicate that the Na concentration decreases as the substrate temperature increases. Hall-effect tests reveal a transition from n-type to p-type conduction when the growth temperature ... [J. Appl. Phys. 106, 093508 (2009)] published Fri Nov 6, 2009.
Effect of ultraviolet irradiation on luminescence properties of undoped ZnS and ZnS:Ag nanoparticles
Hua Qu, Lixin Cao, Ge Su, Wei Liu, Yuanguang Sun et al.
Undoped ZnS and ZnS:Ag nanoparticles have been prepared through hydrothemal synthesis. The changes of luminescence properties induced by ultraviolet irradiation have been investigated. For both samples, the initial slight increase in luminescence is ascribed to the fast electron filling, while the s ... [J. Appl. Phys. 106, 093506 (2009)] published Fri Nov 6, 2009.
Investigation of doped calcium aluminosilicate glass: A coupling between thermal-expansion and thermal-diffusion models for assessment of nonradiative relaxation time and characteristic diffusion time
N. E. Souza Filho, A. C. Nogueira, J. H. Rohling, M. L. Baesso, A. N. Medina et al.
This paper discusses the use of photoacoustic models to obtain the nonradiative relaxation time (tau) and characteristic diffusion time (tau) for a sample showing visible absorption bands from fluorescent ion-doped low-silica calcium aluminosilicate glass. Two models allowing phase shift analyses, t ... [J. Appl. Phys. 106, 093105 (2009)] published Fri Nov 6, 2009.
How to measure quantum yields in scattering media: Application to the quantum yield measurement of fluorescein molecules encapsulated in sub-100 nm silica particles
M. Martini, M. Montagna, M. Ou, O. Tillement, S. Roux et al.
Dye quantum yield is generally measured using the method of Williams, which consists in comparing the absorbance and the emission of the dye to test with those of a reference. Unfortunately, this method is no more applicable when the sample presents some significant scattering which is, for instance ... [J. Appl. Phys. 106, 094304 (2009)] published Fri Nov 6, 2009.
Optically active Er ions in SiO codoped with Si nanoclusters
D. Navarro-Urrios, Y. Lebour, O. Jambois, B. Garrido, A. Pitanti et al.
Optical properties of directly excited erbium (Er) ions have been studied in silicon rich silicon oxide materials codoped with Er. The spectral dependence of the direct excitation cross section (sigma) of the Er atomic I-->I transition (around 0.98 [mu]m) has been measured by time resolved [mu]-pho ... [J. Appl. Phys. 106, 093107 (2009)] published Fri Nov 6, 2009.
Nanoindentation-induced phase transformation in relaxed and unrelaxed ion-implanted amorphous germanium
D. J. Oliver, J. E. Bradby, S. Ruffell, J. S. Williams, and P. Munroe
We have investigated nanoindentation-induced plastic deformation in amorphous germanium (a-Ge) prepared by high-energy self-ion implantation. Using cross-sectional transmission electron microscopy, micro-Raman spectroscopy, and force-displacement curve analysis, we find strong evidence for a pressur ... [J. Appl. Phys. 106, 093509 (2009)] published Fri Nov 6, 2009.
Reaction pathway analysis for dislocation nucleation from a Ni surface step
Shotaro Hara, Satoshi Izumi, and Shinsuke Sakai
Threshold strain required for a thermally activated dislocation nucleation from a Ni surface step has been measured using an atomistic-based reaction pathway analysis. We show that the saddle-point configuration and the stress-dependent activation energy are strongly influenced by the presence of a ... [J. Appl. Phys. 106, 093507 (2009)] published Fri Nov 6, 2009.
Multiresonant Spinor Dynamics in a Bose-Einstein Condensate
C. Klempt, O. Topic, G. Gebreyesus, M. Scherer, T. Henninger et al.
We analyze the spinor dynamics of a Rb F=2 condensate initially prepared in the m=0 Zeeman sublevel. We show that this dynamics, characterized by the creation of correlated atomic pairs in m=1, presents an intriguing multiresonant magnetic-field dependence induced by the trap inhomogeneity. This dep ... [Phys. Rev. Lett. 103, 195302 (2009)] published Fri Nov 6, 2009.
Nature of Atomic Bonding and Atomic Structure in the Phase-Change GeSbTe Glass
M. Xu, Y. Q. Cheng, H. W. Sheng, and E. Ma
Using electronic structure calculations, we demonstrate a global valence alternation in the amorphous GeSbTe, a prototype phase-change alloy for data storage. The resulting p bonding profoundly influences the local atomic structure, leading to right-angle components similar to those in the crystalli ... [Phys. Rev. Lett. 103, 195502 (2009)] published Fri Nov 6, 2009.
Structure of self-interstitial atom clusters in iron and copper
Akiyuki Takahashi and Nasr M. Ghoniem
The dislocation core structure of self-interstitial atom (SIA) clusters in bcc iron and fcc copper is determined using the hybrid ab initio continuum method of Banerjee et al. [Philos. Mag. 87, 4131 (2007)]. To reduce reliance on empirical potentials and to facilitate predictions of the effects of l ... [Phys. Rev. B 80, 174104 (2009)] published Thu Nov 5, 2009.
Dipolar particles in an external field: Molecular dynamics simulation and mean field theory
Ran Jia and Reinhard Hentschke
Using molecular dynamics computer simulation we compute gas-liquid phase coexistence curves for the Stockmayer fluid in an external electric field. We observe a field-induced shift of the critical temperature DeltaT. The sign of DeltaT depends on whether the potential or the surface charge density i ... [Phys. Rev. E 80, 051502 (2009)] published Thu Nov 5, 2009.
Electrode polarization and charge transport at solid interfaces
A. Serghei, M. Tress, J. R. Sangoro, and F. Kremer
A quantitative description is suggested for electrode polarization, an ubiquitous phenomenon which takes place at the interface between a metallic and an ionic conductor and results in an increase by many orders of magnitude in the net dielectric response of the sample cell. Based on the fact that d ... [Phys. Rev. B 80, 184301 (2009)] published Thu Nov 5, 2009.
Icosahedral ordering in liquid iron studied via x-ray scattering and Monte Carlo simulations
Masanori Inui, Kenji Maruyama, Yukio Kajihara, and Masaru Nakada
X-ray diffraction measurements were carried out for liquid iron near the melting temperature and atomic configurations were constructed from the structure factor S(Q) obtained, by reverse Monte Carlo modeling and Monte Carlo simulation with the effective pair potential deduced by the inverse method. ... [Phys. Rev. B 80, 180201 (2009)] published Thu Nov 5, 2009.
Imaging properties of lossless double-negative metamaterial wedges: Analytical and numerical investigation
Dimitrios L. Sounas, Nikolaos V. Kantartzis, and Theodoros D. Tsiboukis
The superlensing characteristics of a lossless double-negative metamaterial wedge are examined in this paper via an analytical technique. The algorithm incorporates the Kontorovich-Lebedev (KL) transform in a mathematically consistent manner whereas the role of the radiation condition on its correct ... [Phys. Rev. B 80, 195105 (2009)] published Thu Nov 5, 2009.
Time dependence of the ground-state population statistics of condensed microcavity polaritons
Nguyen Duy Vy, H. Thien Cao, D. B. Tran Thoai, and H. Haug
The semiclassical approach consisting of Boltzmann equations for the excited states and the ground state supplemented by a Master equation for the probability distribution of the condensate population is solved for picosecond pulsed microcavity polaritons. With the simple birth- and death-type Maste ... [Phys. Rev. B 80, 195306 (2009)] published Thu Nov 5, 2009.
Cooling dynamics and thermal interface resistance of glass-embedded metal nanoparticles
Vincent Juve, Mattia Scardamaglia, Paolo Maioli, Aurelien Crut, Samy Merabia et al.
The cooling dynamics of glass-embedded noble metal nanoparticles with diameters ranging from 4 to 26 nm were studied using ultrafast pump-probe spectroscopy. Measurements were performed probing away from the surface plasmon resonance of the nanoparticles to avoid spurious effects due to glass heatin ... [Phys. Rev. B 80, 195406 (2009)] published Thu Nov 5, 2009.
Measurement of the Knight field and local nuclear dipole-dipole field in an InGaAs/GaAs quantum dot ensemble
T. Auer, R. Oulton, A. Bauschulte, D. R. Yakovlev, M. Bayer et al.
We present a comprehensive investigation of the electron-nuclear system of negatively charged InGaAs/GaAs self-assembled quantum dots (QDs) under the influence of weak external magnetic fields (up to 3 mT). We demonstrate that, in contrast to conventional semiconductor systems, these small fields ha ... [Phys. Rev. B 80, 205303 (2009)] published Thu Nov 5, 2009.
Infrared optical properties of chromium nanoscale films with a phase transition
Robert LovrinCic and Annemarie Pucci
Thickness-dependent infrared spectra measured during growth of Cr on diamond C(100) under ultrahigh vacuum conditions reveal a structural phase transition from a discontinuous phase to the crystalline bulk one with Drude-type optical properties. The thickness of 2.5 nm of the observed phase transiti ... [Phys. Rev. B 80, 205404 (2009)] published Thu Nov 5, 2009.
Tunnel coupling in an ensemble of vertically aligned quantum dots at room temperature
V. V. Nikolaev, N. S. Averkiev, M. M. Sobolev, I. M. Gadzhiyev, I. O. Bakshaev et al.
We report unambiguous observation of the formation of mixed electronic states in an ensemble of self-assembled vertically aligned quantum dots at room temperature. Three closely spaced layers containing stacked In(Ga)As/GaAs quantum dots are placed in the active region of a two-section semiconductor ... [Phys. Rev. B 80, 205304 (2009)] published Thu Nov 5, 2009.
Ligand isotope structure of the optical F-->D transition in EuCl6HO
R. L. Ahlefeldt, A. Smith, and M. J. Sellars
The structure of the F-->D transition of Eu in EuCl6HO is investigated in crystals with three different isotopic compositions [natural abundance (0.2% O, 0.01%H), 1.9% O, and 0.06% H]. Raman-heterodyne-detected NMR is used to identify shifts caused by isotopes of the ligands O and H in sites neighbo ... [Phys. Rev. B 80, 205106 (2009)] published Thu Nov 5, 2009.
Enhanced thermal stability of Pt electrodes for flat epitaxial biferroic-YMnO/Pt heterostructures
R. Bachelet, R. Muralidharan, F. Rigato, N. Dix, X. Marti et al.
We have investigated the thermal stability of platinum electrodes on oxide substrates for oxide-based devices. We show that flat epitaxial Pt(111) bottom electrodes, deposited on SrTiO(111) and AlO(0001) substrates, can be stable against dewetting up to usual oxide-deposition temperatures (T) by inc ... [Appl. Phys. Lett. 95, 181907 (2009)] published Thu Nov 5, 2009.
Determination and enhancement of the capacitance contributions in carbon nanotube based electrode systems
M. Hoefer and P. R. Bandaru
We characterize the methodology of, and a possible way to enhance, the capacitance of carbon nanotube (CNT) electrode based electrochemical capacitors. Argon irradiation was used to controllably incorporate extrinsic defects into CNTs and increase the magnitude of both the pseudocapacitance and doub ... [Appl. Phys. Lett. 95, 183108 (2009)] published Thu Nov 5, 2009.
Thermal properties of char obtained by pyrolysis: A molecular dynamics simulation study
Maxim A. Makeev and Deepak Srivastava
The thermal conductivity of pyrolytic char obtained by ultrahigh temperature decomposition of polyethylene specimen via molecular dynamics simulations is investigated as a function of temperature and microstructural characteristics. We find that the simulated thermal conductivity dependence on the a ... [Appl. Phys. Lett. 95, 181908 (2009)] published Thu Nov 5, 2009.
Individual charge-trapping dislocations in an ionic insulator
Zhongchang Wang, Susumu Tsukimoto, Mitsuhiro Saito, and Yuichi Ikuhara
Insulating oxide materials find widespread technological applications where how their inside dislocations behave are known to influence or control performance. Here we demonstrate, by first-principles calculations on MgO, that individual dislocations can trap charges within empty space around their ... [Appl. Phys. Lett. 95, 184101 (2009)] published Thu Nov 5, 2009.
Engineering single photon emitters by ion implantation in diamond
B. Naydenov, R. Kolesov, A. Batalov, J. Meijer, S. Pezzagna et al.
Diamond provides unique technological platform for quantum technologies including quantum computing and communication. Controlled fabrication of optically active defects is a key element for such quantum toolkit. Here we report the production of single color centers emitting in the blue spectral reg ... [Appl. Phys. Lett. 95, 181109 (2009)] published Thu Nov 5, 2009.
Ultrafast imaging of photoelectron packets generated from graphite surface
Ramani K. Raman, Zhensheng Tao, Tzong-Ru Han, and Chong-Yu Ruan
We present an electron projection imaging method to study the ultrafast evolution of photoelectron density distribution and transient fields near the surface. The dynamical profile of the photoelectrons from graphite reveals an origin of a thermionic emission, followed by an adiabatic process leadin ... [Appl. Phys. Lett. 95, 181108 (2009)] published Thu Nov 5, 2009.
Quantum confined Stark effect and corresponding lifetime reduction in a single InGaN quantum disk
Mark J. Holmes, Young S. Park, Jamie H. Warner, and Robert A. Taylor
Time-integrated and time-resolved microphotoluminescence studies were carried out on InGaN quantum disks embedded in GaN nanocolumns grown by molecular beam epitaxy. Emission at ~3.33 eV from confined states was detected and observed to blueshift with excitation power; a result of charge screening ... [Appl. Phys. Lett. 95, 181910 (2009)] published Thu Nov 5, 2009.
Direct Observation of the Critical Relaxation of Polarization Clusters in BaTiO Using a Pulsed X-Ray Laser Technique
K. Namikawa, M. Kishimoto, K. Nasu, E. Matsushita, R. Z. Tai et al.
We have developed a new method to investigate the relaxation time of the dipole moment in polarization clusters in BaTiO. Time correlation of speckle intensities was measured by the use of a double pulsed soft x-ray laser. The evolution of the relaxation time of the dipole moment near the Curie temp ... [Phys. Rev. Lett. 103, 197401 (2009)] published Thu Nov 5, 2009.
Experimental and theoretical investigations on the epitaxial growth of 4,4 stilbenedicarboxylic acid molecules on Au(111)
Yan Feng Zhang, Yong Yang, Yoshiyuki Kawazoe, and Tadahiro Komeda
We report on scanning tunneling microscope observations of the epitaxial growth of 4,4 stilbenedicarboxylic acid (SDA) molecules on Au(111), with the coverage ranges from submonolayer to one monolayer. The surface assembly evolves from one-dimensional molecular chains to striped islands and finally ... [J. Chem. Phys. 131, 174706 (2009)] published Thu Nov 5, 2009.
The Landau free energy of a melt of graft copolymers
M. A. Aliev and S. I. Kuchanov
New graphical algorithm is proposed to find vertex functions which are the coefficients of expansion of the Landau free energy of polydisperse multigraft copolymers whose macromolecules comprise an arbitrary number of types of side chains. This algorithm imposes no restriction on length distribution ... [J. Chem. Phys. 131, 174111 (2009)] published Thu Nov 5, 2009.
Hydrogen bonding in acetone clusters probed by near-edge x-ray absorption fine structure spectroscopy in the carbon and oxygen K-edge regions
Y. Tamenori, O. Takahashi, K. Yamashita, T. Yamaguchi, K. Okada et al.
Hydrogen bonding in acetone clusters was investigated using near-edge x-ray absorption fine structure (NEXAFS) spectroscopy and density functional theory calculations in the carbon and oxygen K-edge regions. The partial-ion-yield (PIY) curves of the cluster ions were measured as the NEXAFS spectra o ... [J. Chem. Phys. 131, 174311 (2009)] published Thu Nov 5, 2009.
Phase equilibria in DOPC/DPPC: Conversion from gel to subgel in two component mixtures
Miranda L. Schmidt, Latifa Ziani, Michelle Boudreau, and James H. Davis
Biological membranes contain a mixture of phospholipids with varying degrees of hydrocarbon chain unsaturation. Mixtures of long chain saturated and unsaturated lipids with cholesterol have attracted a lot of attention because of the formation of two coexisting fluid bilayer phases in such systems o ... [J. Chem. Phys. 131, 175103 (2009)] published Thu Nov 5, 2009.
Diffusion behavior in a liquid-liquid interfacial crystallization by molecular dynamics simulations
Akira Kitayama, Shinya Yamanaka, Kazunori Kadota, Atsuko Shimosaka, Yoshiyuki Shirakawa et al.
Interfacial crystallization, such as surface crystallization in solution (solid-liquid) and liquid-liquid crystallization, gives us an asymmetric reaction field and is a technique for morphology control of crystals. In the liquid-liquid crystallization, the concentration distribution of solute ions ... [J. Chem. Phys. 131, 174707 (2009)] published Thu Nov 5, 2009.
Electro-optic measurement of terahertz pulse energy distribution
J. H. Sun, J. G. Gallacher, G. J. H. Brussaard, N. Lemos, R. Issac et al.
An accurate and direct measurement of the energy distribution of a low repetition rate terahertz electromagnetic pulse is challenging because of the lack of sensitive detectors in this spectral range. In this paper, we show how the total energy and energy density distribution of a terahertz electrom ... [Rev. Sci. Instrum. 80, 113103 (2009)] published Thu Nov 5, 2009.
Study of low temperature growth of III-V alloys for transparent layers
L. Wu, S. Iyer, J. Li, K. Gibson, J. Reppert et al.
The authors report on the successful growth of wide band gap III-V alloy systems on glass substrates at low growth temperatures that may be suitably exploited for the realization of novel high performance and stable optoelectronic devices. A systematic investigation on the growth of GaAs, GaAlAs(N), ... [J. Vac. Sci. Technol. B 27, 2375 (2009)] published Thu Nov 5, 2009.
First-principles molecular dynamics simulations at solid-liquid interfaces with a continuum solvent
Veronica M. Sanchez, Mariela Sued, and Damian A. Scherlis
Continuum solvent models have become a standard technique in the context of electronic structure calculations, yet no implementations have been reported capable to perform molecular dynamics at solid-liquid interfaces. We propose here such a continuum approach in a density functional theory framewor ... [J. Chem. Phys. 131, 174108 (2009)] published Wed Nov 4, 2009.
Neutron scattering study of the dynamics of a polymer melt under nanoscopic confinement
Margarita Krutyeva, Jaime Martin, Arantxa Arbe, Juan Colmenero, Carmen Mijangos et al.
Poly(ethylene oxide) confined in an anodic aluminum oxide solid matrix has been studied by different neutron scattering techniques in the momentum transfer (Q-vector) range 0.2<=Q=|Q-vector |<=1.9 A. The cylindrical pores of the matrix present a diameter (40 nm) much smaller than their length (150 ... [J. Chem. Phys. 131, 174901 (2009)] published Wed Nov 4, 2009.
Charge transfer satellite in Pr@C metallofullerene observed using resonant x-ray emission spectroscopy
H. Yamaoka, H. Sugiyama, Y. Kubozono, A. Kotani, R. Nouchi et al.
Resonant x-ray emission spectroscopy (RXES) was performed on the metallofullerene Pr@C at the Pr L absorption edge. We verify not only nearly three-electron charge transfers from the metal to the cage but also back-electron transfer observed as a charge transfer satellite. The results are compared t ... [Phys. Rev. B 80, 205403 (2009)] published Wed Nov 4, 2009.
Electric-field induced modulation of the magneto-optical Kerr effect in a (Zn,Be,Mn)Se/GaAs spintronic device
J. H. Versluis, A. V. Kimel, A. Kirilyuk, P. Grabs, F. Lehmann et al.
It is shown that when spin-polarized electrons are injected from a (Zn,Be,Mn)Se spin-aligner into GaAs, the magneto-optical Kerr effect from (Zn,Be,Mn)Se/GaAs spintronic device is strongly affected by a large electric-field at the (Zn,Be,Mn)Se/GaAs interface. This field causes the magneto-optical si ... [Phys. Rev. B 80, 193303 (2009)] published Wed Nov 4, 2009.
Superhard diamondlike BC: A first-principles investigation
Chao Jiang, Zhijun Lin, and Yusheng Zhao
We perform first-principles density-functional calculations to identify the possible crystal structure of a superhard diamondlike BC phase, which was recently synthesized under high-pressure and high-temperature conditions. Interestingly, we find only a small total-energy difference between the ener ... [Phys. Rev. B 80, 184101 (2009)] published Wed Nov 4, 2009.
Finding the low-energy structures of Si[001] symmetric tilted grain boundaries with a genetic algorithm
Jian Zhang, Cai-Zhuang Wang, and Kai-Ming Ho
We developed a global structure optimization method, genetic algorithm, for a fast and efficient prediction of grain-boundary structures. Using this method we predicted the most stable structures and a number of low-energy metastable structures for Si[001] symmetric tilted grain boundaries with vari ... [Phys. Rev. B 80, 174102 (2009)] published Wed Nov 4, 2009.
Negative impurity ions in liquid He
F. Ancilotto, M. Barranco, and M. Pi
We present theoretical results, based on zero-temperature density-functional theory, for the formation and properties of a negative impurity ion in bulk liquid He. We first consider Ca which, due to its very low electron affinity, does not easily form a negative ion in vacuum. We show that a neutral ... [Phys. Rev. B 80, 174504 (2009)] published Wed Nov 4, 2009.
Relationship between low-temperature boson heat capacity peak and high-temperature shear modulus relaxation in a metallic glass
A. N. Vasiliev, T. N. Voloshok, A. V. Granato, D. M. Joncich, Yu. P. Mitrofanov et al.
Low-temperature (2 K<=T<=350 K) heat capacity and room-temperature shear modulus measurements (nu=1.4 MHz) have been performed on bulk PdCuP in the initial glassy, relaxed glassy, and crystallized states. It has been found that the height of the low-temperature Boson heat capacity peak strongly c ... [Phys. Rev. B 80, 172102 (2009)] published Wed Nov 4, 2009.
Barrier width dependence of the donor binding energy of hydrogenic impurity in wurtzite InGaN/GaN quantum dot
Congxin Xia, Zaiping Zeng, and Shuyi Wei
Within the framework of the effective-mass approximation, the barrier width dependence of the donor binding energy of hydrogenic impurity in a cylindrical wurtzite (WZ) InGaN/GaN strained quantum dot (QD) is calculated by means of a variational procedure, considering the strong built-in electric fie ... [J. Appl. Phys. 106, 094301 (2009)] published Wed Nov 4, 2009.
Three-Dimensional Multiple Scattering of Elastic Waves by Spherical Inclusions
Zunping Liu and Liang-Wu Cai
This paper extends the scatterer polymerization methodology to three-dimensional multiple scattering of elastic waves by spherical inclusions. The methodology was originally developed for analyzing multiple scattering of elastic antiplane shear waves in two-dimensional spaces. The analytically exact ... [J. Vib. Acoust. 131, 061005 (2009)] published Wed Nov 4, 2009.
Contributions of Inter- and Intraband Excitations to Electron Heat Capacity and Electron-Phonon Coupling in Noble Metals
Patrick E. Hopkins
This work examines the effects of photonically induced interband excitations from the d-band to states at the Fermi energy on thermophysical properties in noble metals. The change in the electron population in the d-band and the conduction band causes a change in electron heat capacity and electron- ... [J. Heat Transfer 132, 014504 (2009)] published Wed Nov 4, 2009.
Composition-dependent dielectric properties of RbTiOPO single crystals
Jna. Gavalda, J. J. Carvajal, X. Mateos, M. Aguilo, and F. Diaz
We measured the ionic conductivity for two single crystals of RbTiOPO grown in self-fluxes with different chemical composition. Ionic conductivity depended on the composition of the self-flux solution in which the crystal was grown. One of the samples showed an anisotropic behavior along the three c ... [Appl. Phys. Lett. 95, 182902 (2009)] published Tue Nov 3, 2009.
Optical confirmation of biaxial nematic (N) phase in a bent-core mesogen
Yun Jang, Vitaly P. Panov, Antoni Kocot, J. K. Vij, A. Lehmann et al.
A bent-core mesogen with different end groups has been studied for different surface conditions in both planar and homeotropic cells using techniques for measuring biaxiality and optical switching. Biaxial nematic phase observed in between the uniaxial nematic and smectic phases is evidenced by a sh ... [Appl. Phys. Lett. 95, 183304 (2009)] published Tue Nov 3, 2009.
Spontaneous buildup of surface potential with a thin film of a zwitterionic molecule giving noncentrosymmetric crystal structure
Jun'ya Tsutsumi, Hiroyuki Yoshida, Richard Murdey, and Naoki Sato
Surface potentials were examined using the Kelvin method for thin films of zwitterionic molecules, pyridinium 1,3-dihydro-1,3-dioxo-2H-inden-2-ylide (PI or IPB) and two nitrogen-substituted derivatives. Spontaneous buildup of the surface potential on the film (5.5 V at a film thickness of 300 nm) wa ... [Appl. Phys. Lett. 95, 182901 (2009)] published Tue Nov 3, 2009.
Optimizing the thermoelectric efficiency of icosahedral quasicrystals and related complex alloys
Enrique Macia
In this work we analyze the potential role of quasicrystals and related alloys in thermoelectric material research. Relatively large figure of merit values are expected for those samples exhibiting two properly located narrow features in the density of states close to the Fermi level. It is expected ... [Phys. Rev. B 80, 205103 (2009)] published Tue Nov 3, 2009.
Dithering-amplitude dependence of STM-regulated dynamic lateral force microscopy maps on Si(111)7 x 7
Naruo Sasaki, Shigeki Kawai, and Hideki Kawakatsu
Model simulation of dynamic lateral force microscopy (DLFM) regulated by scanning tunneling microscopy (STM) has been performed. The simulated STM/DLFM maps on Si(111)7 x 7 exhibit marked transitions depending on the lateral dithering amplitude, and they can successfully reproduce the experimentally ... [Phys. Rev. B 80, 193402 (2009)] published Tue Nov 3, 2009.
Comparative study of the surface layer density of liquid surfaces
E. Chacon, E. M. Fernandez, D. Duque, R. Delgado-Buscalioni, and P. Tarazona
Capillary wave fluctuations blur the inherent structure of liquid surfaces in computer simulations. The intrinsic sampling method subtracts capillary wave fluctuations and yields the intrinsic surface structure, leading to a generic picture of the liquid surface. The most relevant magnitude of the m ... [Phys. Rev. B 80, 195403 (2009)] published Tue Nov 3, 2009.
Wave propagation retrieval method for metamaterials: Unambiguous restoration of effective parameters
Andrei Andryieuski, Radu Malureanu, and Andrei V. Lavrinenko
In this Brief report we propose a direct method of effective-parameters restoration that is based on the wave propagation phenomenon. It is easy in implementation, has no unambiguity in retrieving effective properties and is applicable to thick metamaterial (MTM) slabs. The method is validated on th ... [Phys. Rev. B 80, 193101 (2009)] published Tue Nov 3, 2009.
Randomness-induced redistribution of vibrational frequencies in amorphous solids
Valery Ilyin, Itamar Procaccia, Ido Regev, and Yair Shokef
Much of the discussion in the literature of the low-frequency part of the density of states of amorphous solids was dominated for years by comparing measured or simulated density of states to the classical Debye model. Since this model is hardly appropriate for the materials at hand, this created so ... [Phys. Rev. B 80, 174201 (2009)] published Tue Nov 3, 2009.
Off-diagonal long-range order and supersolidity in a quantum solid with vacancies
Yu Shi, Yin Yang, and Shao-Ming Fei
We consider a lattice of bosonic atoms, whose number N may be smaller than the number of lattice sites M. We study the Hartree-Fock wave function built up from localized wave functions w(r) of single atoms, with nearest-neighboring overlap. The zero-momentum particle number is expressed in terms of ... [Phys. Rev. B 80, 174503 (2009)] published Tue Nov 3, 2009.
Density nonlinearities in field theories for a toy model of fluctuating nonlinear hydrodynamics of supercooled liquids
Joonhyun Yeo
We study a zero-dimensional version of the fluctuating nonlinear hydrodynamics (FNH) of supercooled liquids originally investigated by Das and Mazenko (DM) [Shankar P. Das and Gene F. Mazenko Phys. Rev. A 34, 2265 (1986)]. The time-dependent density-like and momentum-like variables are introduced wi ... [Phys. Rev. E 80, 051501 (2009)] published Tue Nov 3, 2009.
In situ high-pressure study of diborane by infrared spectroscopy
Yang Song, Chitra Murli, and Zhenxian Liu
As the simplest stable boron hydride in its condensed phase, diborane exhibits an interesting structural chemistry with uniquely bridged hydrogen bonds. Here we report the first room-temperature infrared (IR) absorption spectra of solid diborane compressed to pressures as high as 50 GPa using a diam ... [J. Chem. Phys. 131, 174506 (2009)] published Tue Nov 3, 2009.
A soft-core GayBerne model for the simulation of liquid crystals by Hamiltonian replica exchange
Roberto Berardi, Claudio Zannoni, Juho S. Lintuvuori, and Mark R. Wilson
The GayBerne (GB) potential has proved highly successful in the simulation of liquid crystal phases, although it is fairly demanding in terms of resources for simulations of large (e.g., N>10) systems, as increasingly required in applications. Here, we introduce a soft-core GB model, which exhibits ... [J. Chem. Phys. 131, 174107 (2009)] published Tue Nov 3, 2009.
Dielectric discontinuity effects on the adsorption of a linear polyelectrolyte at the surface of a neutral nanoparticle
Marianne Seijo, Martin Pohl, Serge Ulrich, and Serge Stoll
The formation of complexes between nanoparticles and polyelectrolytes is a key process for the control of the reactivity of manufactured nanoparticles and rational design of core shell nanostructures. In this work, we investigate the influence of the nanoparticle dielectric constant on the adsorptio ... [J. Chem. Phys. 131, 174704 (2009)] published Tue Nov 3, 2009.
Failure of the constrained equilibrium hypothesis in nucleation
Lawrence S. Bartell
The purpose of this investigation is to find whether solutions of the BeckerDoringTunitskii coupled differential equations can yield results closely paralleling those found in molecular dynamics (MD) simulations of freezing. What is investigated, in particular, is the validity of the constrained equ ... [J. Chem. Phys. 131, 174505 (2009)] published Tue Nov 3, 2009.
Electrophoretic Deposition of Flake-Shaped ZnO Nanoparticles
M. Verde, A. C. Caballero, Y. Iglesias, M. Villegas, and B. Ferrari
ZnO films have been grown on different substrates by using a variety of fabrication techniques. In the present work, we discuss the results on the preparation of ZnO films by electrophoretic deposition (EPD) starting from synthetic flake-shaped nanoparticles. The critical parameters related to the p ... [J. Electrochem. Soc. 157, H55 (2009)] published Tue Nov 3, 2009.
Photoluminescence Properties of Anodic Si Layers Formed in HF/Oxidant Electrolytes
Yan Kai Xu and Sadao Adachi
Anodic layers are formed on p-Si substrates by etching in a HF/MnO or a HF/I mixed solution. The scanning electron microscopy (SEM) image on the HF/MnO-formed layer reveals that the sample has a double-layered [highly resistive top/porous Si (PSi)-like bottom] structure, while the HF/I-formed surfac ... [J. Electrochem. Soc. 157, H44 (2009)] published Tue Nov 3, 2009.
Impact of a surface laser treatment on the dielectric strength of alpha-alumina
Michael Decup, David Malec, and Vincent Bley
The impact of laser treatments on the dielectric strength of alpha-alumina is investigated. In order to induce low surface modifications to strong damages, different laser processing parameters (fluence, assisting gas and its pressure, and laser wavelength) are applied. The experimental results clea ... [J. Appl. Phys. 106, 094103 (2009)] published Tue Nov 3, 2009.
Diffracted magneto-optical Kerr effect of a Ni magnetic grating
J. B. Kim, Y. H. Lu, M. H. Cho, Y. P. Lee, J. Y. Rhee et al.
We report the results of a joint experimental and theoretical investigation focused on the magneto-optical (MO) properties of one-dimensional magnetic grating structure made of Ni. It was found that the longitudinal Kerr rotation of the second-order diffracted beam is nearly three times larger than ... [J. Appl. Phys. 106, 093103 (2009)] published Tue Nov 3, 2009.
Correlated growth of organic material tris (8-hydroxyquinoline) aluminum (Alq3) and its relation to optical properties
Bhargava R. Kanchibotla, K. Garre, and Deeder Aurongzeb
We report slow correlated growth mode in energetic cluster vapor deposited organic light emissive material tris(8-hydroxyquinoline) aluminum from 5 to 100 nm. Phase modulated atomic force microscopy shows very slow grain growth with thickness, with very small phase differences within the film. Fract ... [J. Appl. Phys. 106, 096101 (2009)] published Tue Nov 3, 2009.
Linear and nonlinear optical properties of ZnO/PMMA nanocomposite films
B. Kulyk, B. Sahraoui, O. Krupka, V. Kapustianyk, V. Rudyk et al.
The nanoscale crystals (NCs) of ZnO were embedded into polymethylmethacrylate (PMMA) polymeric matrix and nanocomposite films were prepared by modified spin coating method. The surface of the ZnO/PMMA nanocomposite films has been investigated using atomic force and scanning electron microscopy. The ... [J. Appl. Phys. 106, 093102 (2009)] published Tue Nov 3, 2009.
Lifshitz Point in the Phase Diagram of Resonantly Interacting Li-K Mixtures
K. B. Gubbels, J. E. Baarsma, and H. T. C. Stoof
We consider a strongly interacting Li-K mixture, which is imbalanced both in the masses and the densities of the two fermionic species. At present, it is the experimentalist's favorite for reaching the superfluid regime. We construct an effective thermodynamic potential that leads to excellent agree ... [Phys. Rev. Lett. 103, 195301 (2009)] published Tue Nov 3, 2009.
Bulk viscosity universality and scaling function near the binary liquid consolute point
Jayanta K. Bhattacharjee, Ireneusz Iwanowski, and Udo Kaatze
The hydrodynamical equations and the notion of a frequency dependent complex specific heat near the critical point of binary liquids are used to obtain an expression for the low-frequency bulk viscosity. In this way the interrelations between different theoretical models, treating the critical sound ... [J. Chem. Phys. 131, 174502 (2009)] published Mon Nov 2, 2009.
The isotropic-nematic interface with an oblique anchoring condition
S. M. Kamil, A. K. Bhattacharjee, R. Adhikari, and Gautam I. Menon
We present numerical and analytic results for uniaxial and biaxial orders at the isotropic-nematic interface within GinzburgLandaude Gennes theory. We study the case where an oblique anchoring condition is imposed asymptotically on the nematic side of the interface, reproducing results of previous w ... [J. Chem. Phys. 131, 174701 (2009)] published Mon Nov 2, 2009.
Solid-liquid equilibria and triple points of n-6 Lennard-Jones fluids
Alauddin Ahmed and Richard J. Sadus
Molecular dynamics simulations are reported for the solid-liquid coexistence properties of n-6 Lennard-Jones fluids, where n=12, 11, 10, 9, 8, and 7. The complete phase behavior for these systems has been obtained by combining these data with vapor-liquid simulations. The influence of n on the solid ... [J. Chem. Phys. 131, 174504 (2009)] published Mon Nov 2, 2009.
First-principles study of methane dehydrogenation on a bimetallic Cu/Ni(111) surface
Wei An, X. C. Zeng, and C. Heath Turner
We present density-functional theory calculations of the dehydrogenation of methane and CH (x=13) on a Cu/Ni(111) surface, where Cu atoms are substituted on the Ni surface at a coverage of (1/4) monolayer. As compared to the results on other metal surfaces, including Ni(111), a similar activation me ... [J. Chem. Phys. 131, 174702 (2009)] published Mon Nov 2, 2009.
Structure and optical properties of core-shell bimetallic AgNi clusters: Comparison with pure silver and nickel clusters
M. Harb, F. Rabilloud, and D. Simon
We present the structural, electronic, and optical properties of bimetallic AgNi (n<=7) clusters investigated in the framework of the density functional theory (DFT) (DFT and time-dependent DFT). The structure of AgNi clusters is found to be governed essentially by the formation of a Ni-core surroun ... [J. Chem. Phys. 131, 174302 (2009)] published Mon Nov 2, 2009.
Kinetics of a transient silicide during the reaction of Ni thin film with (100)Si
Dominique Mangelinck, Khalid Hoummada, and Ivan Blum
In situ measurements of the kinetics of the transient theta-NiSi phase formation have been obtained by x-ray diffraction and differential scanning calorimetry. A possible mechanism for the transient phase is proposed. It allows to simulate the growth and the consumption of the theta-NiSi during the ... [Appl. Phys. Lett. 95, 181902 (2009)] published Mon Nov 2, 2009.
Pressure enhancement of the isostructural cubic decomposition in TiAlN
B. Alling, M. Oden, L. Hultman, and I. A. Abrikosov
The influence of pressure on the phase stabilities of TiAlN solid solutions has been studied using first principles calculations. We find that the application of hydrostatic pressure enhances the tendency for isostructural decomposition, including spinodal decomposition. The effect originates in the ... [Appl. Phys. Lett. 95, 181906 (2009)] published Mon Nov 2, 2009.
Carrier relaxation dynamics of ZnCdSe/C core/shell nanocrystals with phase separation as studied by time-resolved cathodoluminescence
Y. Estrin, D. H. Rich, O. Moshe, Sayan Bhattacharyya, and A. Gedanken
The optical properties and carrier relaxation kinetics of ZnCdSe/C core/shell nanocrystals with compositional phase separation occurring on a ~15 nm size scale were examined with time-resolved cathodoluminescence (CL) spectroscopy and imaging. The CL spectral lineshape was found to depend on the le ... [Appl. Phys. Lett. 95, 181903 (2009)] published Mon Nov 2, 2009.
Optical spectroscopy of PrFe(BO): Crystal-field and anisotropic Pr-Fe exchange interactions
M. N. Popova, T. N. Stanislavchuk, B. Z. Malkin, and L. N. Bezmaternykh
High-resolution polarized optical absorption spectra of PrFe(BO) in the paramagnetic and antiferromagnetic phases are reported. The measured energies of the crystal-field (CF) levels within the 4f configuration of Pr in the paramagnetic PrFe(BO) are described by the CF model that involves the 4f/4f5 ... [Phys. Rev. B 80, 195101 (2009)] published Mon Nov 2, 2009.
Molecular dynamics investigation of mixed-alkali borate glasses: Short-range order structure and alkali-ion environments
A. Vegiri, C.-P. E. Varsamis, and E. I. Kamitsos
Structural properties of mixed-alkali borate glasses, 0.3[(1x)LiO-xCsO]0.7BO and 0.3[(1x)LiO-xNaO]0.7BO, have been studied by molecular dynamics simulations at T=300 K and for several values of the alkali mixing parameter, x, to explore structural foundations of the mixed-alkali effect (MAE). The s ... [Phys. Rev. B 80, 184202 (2009)] published Mon Nov 2, 2009.
Effects of Postdeposition Annealing in Argon Ambient on Metallorganic Decomposed CeO Gate Spin Coated on Silicon
H. J. Quah, K. Y. Cheong, Z. Hassan, Z. Lockman, F. A. Jasni et al.
Cerium oxide (CeO) solution was prepared by cerium(III) acetylacetonate hydrate, methanol, and acetic acid as the starting materials via the metallorganic decomposition (MOD) method. Postdeposition annealing was performed onto the MOD-derived CeO films deposited onto n-type Si substrates at differen ... [J. Electrochem. Soc. 157, H6 (2009)] published Mon Nov 2, 2009.
Dynamic many-body theory: Pair fluctuations in bulk He
C. E. Campbell and E. Krotscheck
Dynamical excitations in bulk liquid He are investigated by using a manifestly microscopic theory of excitations that includes multiple-phonon scattering. The wave function of the dynamic system is represented in terms of one- and two-body excitation amplitudes. Equations of motion for the linear re ... [Phys. Rev. B 80, 174501 (2009)] published Mon Nov 2, 2009.
Predicted structure and stability of ABO delta-phase compositions
C. R. Stanek, C. Jiang, B. P. Uberuaga, K. E. Sickafus, A. R. Cleave et al.
A combination of atomistic simulation techniques has been employed to predict ordered structures for a series of ABO delta-phase compounds, where A is a 3+ cation ranging in size from Sc to Ho and B is a 4+ cation ranging from Ti to Zr. Experimentally, a fully ordered cation structure has yet to be ... [Phys. Rev. B 80, 174101 (2009)] published Mon Nov 2, 2009.
Materials in extreme environments
Russell J. Hemley, George W. Crabtree, and Michelle V. Buchanan
Nature is rich with examples of phenomena and environments we might consider extreme, at least from our familiar experience on Earth's surface: large fluxes of radiation and particles from the Sun, explosive asteroid collisions in space, volcanic eruptions that originate deep underground, extraordin ... [Phys. Today 62, 32 (2009)] published Mon Nov 2, 2009.
Complexities of cell differentiation
Sebastian Doniach
Abstract not available. [Phys. Today 62, 12 (2009)] published Mon Nov 2, 2009.
Modeling dipolar and quadrupolar defect structures generated by chiral islands in freely suspended liquid crystal films
N. M. Silvestre, P. Patricio, M. M. Telo da Gama, A. Pattanaporkratana, C. S. Park et al.
We report a detailed theoretical analysis of quadrupolar interactions observed between islands, which are disklike inclusions of extra layers, floating in thin, freely suspended smectic-C liquid crystal films. Strong tangential anchoring at the island boundaries results in a strength +1 chiral defec ... [Phys. Rev. E 80, 041708 (2009)] published Fri Oct 30, 2009.
Renormalized field theory of collapsing directed randomly branched polymers
Hans-Karl Janssen, Frank Wevelsiep, and Olaf Stenull
We present a dynamical field theory for directed randomly branched polymers and in particular their collapse transition. We develop a phenomenological model in the form of a stochastic response functional that allows us to address several interesting problems such as the scaling behavior of the swol ... [Phys. Rev. E 80, 041809 (2009)] published Fri Oct 30, 2009.
Sonoluminescence radiation from different concentrations of sulfuric acid
A. Moshaii, Kh. Imani, and M. Silatani
Sonoluminescence (SL) radiation from an argon bubble in water and in different concentrations of sulfuric acid has numerically been studied to quantify the effects of vapor pressure and viscosity of the liquid on cavitation luminescence in a liquid with controllable vapor pressure and viscosity. For ... [Phys. Rev. E 80, 046325 (2009)] published Fri Oct 30, 2009.