Microstructure analysis of plasma enhanced atomic layer deposition-grown mixed-phase RuTaN barrier for seedless copper electrodeposition
Tonmoy Chakraborty and Eric T. Eisenbraun
Plasma enhanced atomic layer deposition (PEALD)-grown mixed phase RuTaN films has been studied as a direct plate material for Cu electroplating within interconnects. It was seen that these liners behaved as excellent Cu diffusion barrier and could be scaled down to sub-5 nm thicknesses. High resolut ... [J. Vac. Sci. Technol. A 30, 020604 (2012)] published Fri Feb 10, 2012.
Phononic crystal diffraction gratings
Rayisa P. Moiseyenko, Sarah Herbison, Nico F. Declercq, and Vincent Laude
When a phononic crystal is interrogated by an external source of acoustic waves, there is necessarily a phenomenon of diffraction occurring on the external enclosing surfaces. Indeed, these external surfaces are periodic and the resulting acoustic diffraction grating has a periodicity that depends o ... [J. Appl. Phys. 111, 034907 (2012)] published Fri Feb 10, 2012.
First-principles investigation of pressure-induced phase transition in LiNbO
Kaoru Nakamura, Sadao Higuchi, and Toshiharu Ohnuma
We explore the possible high-pressure phase transition of LiNbO using an evolutionary algorithm combined with first-principles calculations. A NaIO-type structure with Pnma symmetry was predicted as the room temperature phase, and an apatite-like structure with P6/m symmetry was predicted as the hig ... [J. Appl. Phys. 111, 033522 (2012)] published Fri Feb 10, 2012.
Influence of size/crystallinity effects on the cation ordering and magnetism of alpha-lithium ferrite nanoparticles
N. Jovic, M. Prekajski, A. Kremenovic, B. JanCar, V. Kahlenberg et al.
alpha-lithium ferrite (LiFeO) nanoparticles have been prepared using two synthesis routes: citrate gel decomposition as well as the Pechini method. Analysis of HRTEM images of the particles showed that they have a core/shell structure, an average size of ~10 nm and stacking faults parallel to the (1 ... [J. Appl. Phys. 111, 034313 (2012)] published Fri Feb 10, 2012.
Critical lines for an unequal size of molecules in a binary gas-liquid mixture around the van Laar point using the combination of the Tompa model and the van der Waals equation
Mustafa Gencaslan and Mustafa Keskin
We combine the modified Tompa model with the van der Waals equation to study critical lines for an unequal size of molecules in a binary gas-liquid mixture around the van Laar point. The van Laar point is coined by Meijer and it is the only point at which the mathematical double point curve is stabl ... [J. Chem. Phys. 136, 064106 (2012)] published Fri Feb 10, 2012.
Young-Type Interference for Scattering of Fast Helium Atoms from an Oxygen Covered Mo(112) Surface
J. Seifert and H. Winter
In studies on two structures of oxygen adsorbates on Mo(112), we demonstrate the potential of fast atom diffraction to derive the surface unit cell size and its symmetry. Helium atoms with energies of 12 keV are scattered from an adsorbate covered Mo(112) surface along low indexed surface directions ... [Phys. Rev. Lett. 108, 065503 ] published .
Critical behavior of a three-dimensional hardcore-cylinder composite system
Jaime Silva, Ricardo Simoes, and Senentxu Lanceros-Mendez
In this work the critical indices beta, gamma, and nu for a three-dimensional (3D) hardcore cylinder composite system with short-range interaction have been obtained. In contrast to the 2D stick system and the 3D hardcore cylinder system, the determined critical exponents do not belong to the same u ... [Phys. Rev. E 85, 021115 ] published .
Continuous universality in nonequilibrium relaxational dynamics of O(2) symmetric systems
Niladri Sarkar and Abhik Basu
We elucidate a nonconserved relaxational nonequilibrium dynamics of a O(2) symmetric model. We drive the system out of equilibrium by introducing a nonzero noise cross correlation of amplitude D in a stochastic Langevin description of the system, while maintaining the O(2) symmetry of the order para ... [Phys. Rev. E 85, 021113 ] published .
Phonon Raman scattering of RCrO perovskites (R=Y, La, Pr, Sm, Gd, Dy, Ho, Yb, Lu)
M. C. Weber, J. Kreisel, P. A. Thomas, M. Newton, K. Sardar et al.
We report a systematic investigation of orthorhombic perovskite-type RCrO powder samples by Raman scattering for nine different rare earth R cations (R = Y, La, Pr, Sm, Gd, Dy, Ho, Yb, and Lu). The room-temperature Raman spectra and the associated phonon mode assignment provide reference data for st ... [Phys. Rev. B 85, 054303 ] published .
Structural transformation and vibrational properties of BaC at high pressure
I. Efthimiopoulos, K. Kunc, G. V. Vazhenin, E. Stavrou, K. Syassen et al.
We show that the ambient-pressure tetragonal phase of BaC (CaC-type, space group I4/mmm), with sixfold coordination of Ba atoms and C dumbbells, transforms reversibly to a new structure type at 4 GPa; it is an eight-coordinated rhombohedral modification (space group R[overline 3]m), which can be vie ... [Phys. Rev. B 85, 054105 ] published .
Kinetics aspects of initial stage thin gamma-AlO film formation on single crystalline beta-NiAl (110)
Zhongfan Zhang, Keeyoung Jung, Long Li, and Judith C. Yang
The growth kinetics and mechanisms of thermally-grown thin gamma-AlO film at 650 degrees C in air on single-crystalline beta-NiAl (110) was characterized via transmission electron microscopy, X-ray diffractometry, and thermo-gravimetric analyses. The oxidation kinetics as a function of thickness wa ... [J. Appl. Phys. 111, 034312 (2012)] published Thu Feb 9, 2012.
Molecular dynamics simulations of damage production by thermal spikes in Ge
Pedro Lopez, Lourdes Pelaz, Ivan Santos, Luis A. Marques, and Maria Aboy
Molecular dynamics simulation techniques are used to analyze damage production in Ge by the thermal spike process and to compare the results to those obtained for Si. As simulation results are sensitive to the choice of the inter-atomic potential, several potentials are compared in terms of material ... [J. Appl. Phys. 111, 033519 (2012)] published Thu Feb 9, 2012.
Prediction of glass-forming ability and characterization of atomic structure of the Co-Ni-Zr metallic glasses by a proposed long range empirical potential
Dai Ye, Li Jiahao, and Liu Baixin
An interatomic potential is constructed for the Co-Ni-Zr ternary metal system under long range empirical formalism and applied to conduct molecular dynamics simulations and Voronoi tessellations. Using solid solution models with varying solute concentrations, the simulations reveal that the physical ... [J. Appl. Phys. 111, 033521 (2012)] published Thu Feb 9, 2012.
Communication: Angle-resolved thermal dissociative sticking of CH on Pt(111): Further indication that rotation is a spectator to the gas-surface reaction dynamics
J. K. Navin, S. B. Donald, D. G. Tinney, G. W. Cushing, and I. Harrison
Effusive molecular beam measurements of angle-resolved thermal dissociative sticking coefficients for CH impinging on a Pt(111) surface, at a temperature of 700 K, are reported and compared to theoretical predictions. The reactivity falls off steeply as the molecular angle of incidence increases awa ... [J. Chem. Phys. 136, 061101 (2012)] published Thu Feb 9, 2012.
Time-resolved simultaneous polarized and depolarized light scattering system with high sensitivity to optical anisotropy: Application to phase separation of an optically isotropic liquid mixture
Takehito Koyama and Hajime Tanaka
Depolarized light scattering is widely used to probe the spatial correlation of optical anisotropy in crystals, liquid crystals, and viscoelastic materials under stress, and a powerful means to study a non-equilibrium pattern evolution process of such a system. To follow the temporal change in the d ... [J. Chem. Phys. 136, 064509 (2012)] published Thu Feb 9, 2012.
Spin-dependent synchrotron x-ray excitations studied by scanning tunneling microscopy
V. Rose, T. Y. Chien, J. W. Freeland, D. Rosenmann, J. Hiller et al.
The ability to position a sharp probe in close proximity to a sample while the surface is illuminated by synchrotron x-rays opens a path to localized spectroscopy and imaging with chemical and magnetic contrast. We have employed a scanning tunneling microscope for the local study of synchrotron x-ra ... [J. Appl. Phys. 111, 07E304 (2012)] published Thu Feb 9, 2012.
The long range voice coil atomic force microscope
H. Barnard, C. Randall, D. Bridges, and P. K. Hansma
Most current atomic force microscopes (AFMs) use piezoelectric ceramics for scan actuation. Piezoelectric ceramics provide precision motion with fast response to applied voltage potential. A drawback to piezoelectric ceramics is their inherently limited ranges. For many samples this is a nonissue, a ... [Rev. Sci. Instrum. 83, 023705 (2012)] published Thu Feb 9, 2012.
Nanostructure thermal conductivity prediction by Monte Carlo sampling of phonon free paths
Alan J. H. McGaughey and Ankit Jain
We propose a method by which the thermal conductivity of a nanostructure with arbitrary geometry can be predicted through Monte Carlo sampling of the free paths associated with phonon-phonon and phonon-boundary scattering. The required inputs are the nanostructure geometry and the bulk phonon freque ... [Appl. Phys. Lett. 100, 061911 (2012)] published Thu Feb 9, 2012.
Single photon emission from InGaN/GaN quantum dots up to 50 K
Stefan Kremling, Christian Tessarek, Heiko Dartsch, Stephan Figge, Sven Hofling et al.
We have investigated the optical properties of single InGaN quantum dots (QDs) by means of microphotoluminescence ([mu]PL) spectroscopy. The QDs were grown on sapphire substrate using metal organic vapor phase epitaxy. Sharp and isolated single exciton emission lines in the blue spectral range were ... [Appl. Phys. Lett. 100, 061115 (2012)] published Thu Feb 9, 2012.
Spontaneous formation of quantum height manganese gallium islands and atomic chains on N-polar gallium nitride(000[overline [bold 1]])
Abhijit Chinchore, Kangkang Wang, Meng Shi, Yinghao Liu, and Arthur R. Smith
Deposition of manganese onto the gallium-rich, nitrogen-polar GaN(000[overline 1]) surface results in the formation of quantum-height island structures. Two unique island heights differing by one atomic layer are observed, including 0.93 nm high islands which are unstable against the formation of 1. ... [Appl. Phys. Lett. 100, 061602 (2012)] published Thu Feb 9, 2012.
Anomaly of film porosity dependence on deposition rate
Stephen P. Stagon, Hanchen Huang, J. Kevin Baldwin, and Amit Misra
This letter reports an anomaly of film porosity dependence on deposition rate during physical vapor deposition the porosity increases as deposition rate decreases. Using glancing angle deposition of Cu on SiO substrate, the authors show that the Cu film consists of well separated nanorods when the ... [Appl. Phys. Lett. 100, 061601 (2012)] published Thu Feb 9, 2012.
Local structure of nitrogen in N-doped amorphous and crystalline GeTe
Alexander V. Kolobov, Paul Fons, Berangere Hyot, Bernard Andre, Junji Tominaga et al.
The local structure around nitrogen species in N-doped GeTe has been investigated using (soft) x-ray absorption spectroscopy and high-resolution x-ray photoemission spectroscopy. The obtained results demonstrate that while in as-deposited amorphous GeTe nitrogen is predominantly bonded to Ge atoms, ... [Appl. Phys. Lett. 100, 061910 (2012)] published Thu Feb 9, 2012.
Persistence of Covalent Bonding in Liquid Silicon Probed by Inelastic X-Ray Scattering
J. T. Okada, P. H.-L. Sit, Y. Watanabe, Y. J. Wang, B. Barbiellini et al.
Metallic liquid silicon at 1787 K is investigated using x-ray Compton scattering. An excellent agreement is found between the measurements and the corresponding Car-Parrinello molecular dynamics simulations. Our results show persistence of covalent bonding in liquid silicon and provide support for t ... [Phys. Rev. Lett. 108, 067402 ] published .
Glass-Transition Temperature Gradient in Nanocomposites: Evidence from Nuclear Magnetic Resonance and Differential Scanning Calorimetry
Aurelie Papon, Helene Montes, Mohamed Hanafi, Francois Lequeux, Laurent Guy et al.
The slowing-down of the dynamics of a polymer chain near a surface has been observed for many years now. Here we show that the behavior of model nanocomposites can be quantitatively described with a gradient of glass-transition temperature. We describe with a single parameterthe range of this gradie ... [Phys. Rev. Lett. 108, 065702 ] published .
Evidence for a Phase Transition in Silicate Melt at Extreme Pressure and Temperature Conditions
D. K. Spaulding, R. S. McWilliams, R. Jeanloz, J. H. Eggert, P. M. Celliers et al.
Laser-driven shock compression experiments reveal the presence of a phase transition in MgSiO over the pressure-temperature range 300400 GPa and 10 00016 000 K, with a positive Clapeyron slope and a volume change of ~6.3 (2.0) percent. The observations are most readily interpreted as an abrupt liqui ... [Phys. Rev. Lett. 108, 065701 ] published .
Frictionless Flow in a Binary Polariton Superfluid
E. Cancellieri, F. M. Marchetti, M. H. Szymanska, D. Sanvitto, and C. Tejedor
We study the properties of a binary microcavity polariton superfluid coherently injected by two lasers at different momenta and energies. The crossover from the supersonic to the subsonic regime, where motion is frictionless, is described by evaluating the linear response of the system to a weak def ... [Phys. Rev. Lett. 108, 065301 ] published .
Physisorption of benzene on a tin dioxide surface: van der Waals interaction
Matti Viitala, Mikael Kuisma, and Tapio T. Rantala
An adsorption study of the benzene molecule on SnO (110) surfaces with the density functional theory is extended to include the van der Waals interaction. We compare adsorption onto two model surfaces of SnO, oxygen rich (stoichiometric) and oxygen poor (reduced), considered as limiting cases of var ... [Phys. Rev. B 85, 085412 ] published .
Carrier confinement in Ge/Si quantum dots grown with an intermediate ultrathin oxide layer
V. Kuryliuk, O. Korotchenkov, and A. Cantarero
We present computational results for strain effects on charge carrier confinement in GeSi quantum dots (QDs) grown on an oxidized Si surface. The strain and free carrier probability density distributions are obtained using the continuum elasticity theory and the effective-mass approximation implemen ... [Phys. Rev. B 85, 075406 ] published .
Exciton binding energies in chalcopyrite semiconductors
Bernard Gil, Didier Felbacq, and Shigefusa F. Chichibu
The optical spectra of Cu-III-VI chalcopyrite compounds display rich excitonic features in the fundamental direct bandgap energy region. The energy structure of excited excitonic states reported in the literature are reexamined using a calculation of the eigenstates of the hydrogenic problem in the ... [Phys. Rev. B 85, 075205 ] published .
Ground-state characterizations of systems predicted to exhibit L1 or L1 crystal structures
Lance J. Nelson, Gus L. W. Hart, and Stefano Curtarolo
Despite their geometric simplicity, the crystal structures L1 (CuPt) and L1 (CdPt) do not appear as ground states experimentally, except in Cu-Pt. We investigate the possibility that these phases are ground states in other binary intermetallic systems, but overlooked experimentally. Via the synergy ... [Phys. Rev. B 85, 054203 ] published .
Binding and structure of tetramers in the scaling limit
M. R. Hadizadeh, M. T. Yamashita, Lauro Tomio, A. Delfino, and T. Frederico
The momentum-space structure of the Faddeev-Yakubovsky (FY) components of weakly bound tetramers is investigated at the unitary limit using a renormalized zero-range two-body interaction. The results, obtained by considering a given trimer level with binding energy B, provide further support to a un ... [Phys. Rev. A 85, 023610 ] published .
Few-body bound-state stability of dipolar molecules in two dimensions
A. G. Volosniev, D. V. Fedorov, A. S. Jensen, and N. T. Zinner
Bound structures among dipolar molecules in multilayers are a topic of great interest in the light of recent experiments that have demonstrated the feasibility of the setup. While it is known that two molecules in two adjacent layers will always bind, larger complexes have only been scarcely address ... [Phys. Rev. A 85, 023609 ] published .
Structural studies of high-K metastable CoPt thin films with long-range order
Fu-Te Yuan, Jen-Hwa Hsu, Yi-Hung Lin, S. N. Hsiao, and H. Y. Lee
The symmetries of CoPt thin films in different phases, including disordered A1, ordered L1, and L1 were examined by making measurements along the (10.1) diffraction rod. The films were deposited by sputtering on MgO(111) substrates at different temperatures (T). The stacking sequence of close-packed ... [J. Appl. Phys. 111, 07A303 (2012)] published Wed Feb 8, 2012.
Effect of intrinsic tensile stress on (001) orientation in L1 FePt thin films on glass substrates
S. N. Hsiao, S. H. Liu, S. K. Chen, F. T. Yuan, and H. Y. Lee
Single-layered FePt thin films were deposited on glass substrates and subsequently annealed at 800 degrees C for various times in a rapid thermal annealing (RTA) furnace. Near-fully-L1-ordered FePt films were obtained after RTA. The accumulation of the intrinsic tensile stress is mainly contributed ... [J. Appl. Phys. 111, 07A702 (2012)] published Wed Feb 8, 2012.
Multiferroic properties of La-doped BiFeCrO prepared by high-pressure synthesis
Feiming Bai, Lei Shi, Huaiwu Zhang, Zhiyong Zhong, Wendan Wang et al.
Undoped BiFeCrO and 10 at. % La-doped BiFeCrO were prepared by a high-pressure solid-state sintering method. The phase structure, electrical, ferroelectric, and magnetic properties have been investigated. It is shown that doping La can increase the resistivity by three orders of magnitude at room te ... [J. Appl. Phys. 111, 07C702 (2012)] published Wed Feb 8, 2012.
Epitaxial FeGa/GaAs structures via electrochemistry for spintronics applications
K. Sai Madhukar Reddy, Mazin M. Maqableh, and Bethanie J. H. Stadler
In this study, thin films of FeGa (a giant magnetostrictive alloy) were grown on single-crystalline n-GaAs (001) and polycrystalline brass substrates via electrochemical synthesis from ferrous and gallium sulfate electrolytes. Extensive structural characterization using microdiffraction, high-resolu ... [J. Appl. Phys. 111, 07E502 (2012)] published Wed Feb 8, 2012.
Sodium-ion conduction in complex hydrides NaAlH and NaAlH
H. Oguchi, M. Matsuo, S. Kuromoto, H. Kuwano, and S. Orimo
We have studied sodium-ion conduction in complex hydrides NaAlH and NaAlH. The electrical conductivities of these complex hydrides were studied using ac impedance measurements at temperatures up to 363 K for NaAlH and 433 K for NaAlH. Nyquist plots obtained by the measurements indicated the sodium-i ... [J. Appl. Phys. 111, 036102 (2012)] published Wed Feb 8, 2012.
Structural properties and spatial ordering in multilayered ZnMgTe/ZnSe type-II quantum dot structures
U. Manna, I. C. Noyan, Q. Zhang, I. F. Salakhutdinov, K. A. Dunn et al.
We report the structural properties and spatial ordering of multilayer ZnMgTe quantum dots (QDs) embedded in ZnSe, where sub-monolayer quantities of Mg were introduced periodically during growth in order to reduce the valence band offset of ZnTe QDs. The periodicity, period dispersion, individual la ... [J. Appl. Phys. 111, 033516 (2012)] published Wed Feb 8, 2012.
Thermal carrier emission and nonradiative recombinations in nonpolar (Al,Ga)N/GaN quantum wells grown on bulk GaN
P. Corfdir, A. Dussaigne, H. Teisseyre, T. Suski, I. Grzegory et al.
We investigate, via time-resolved photoluminescence, the temperature-dependence of charge carrier recombination mechanisms in nonpolar (Al,Ga)N/GaN single quantum wells (QWs) grown via molecular beam epitaxy on the a-facet of bulk GaN crystals. We study the influence of both QW width and barrier Al ... [J. Appl. Phys. 111, 033517 (2012)] published Wed Feb 8, 2012.
Formation of twins in sapphire under shock wave loading: Atomistic simulations
A. Yu. Kuksin and A. V. Yanilkin
This work is devoted to molecular dynamics (MD) simulation of shock-wave loading of sapphire (alpha-AlO). Defect free sapphire and sapphire with the microcrack are considered. Homogeneous nucleation and growth of rhombohedral twins are observed in single crystal alumina. A fast mechanism of plastic ... [J. Appl. Phys. 111, 033513 (2012)] published Wed Feb 8, 2012.
Elucidation of spin echo small angle neutron scattering correlation functions through model studies
Chwen-Yang Shew and Wei-Ren Chen
Several single-modal Debye correlation functions to approximate part of the overall Debey correlation function of liquids are closely examined for elucidating their behavior in the corresponding spin echo small angle neutron scattering (SESANS) correlation functions. We find that the maximum length ... [J. Chem. Phys. 136, 064506 (2012)] published Wed Feb 8, 2012.
Structure and properties of metal-exchanged zeolites studied using gradient-corrected and hybrid functionals. III. Energetics and vibrational spectroscopy of adsorbates
Florian Goltl and Jurgen Hafner
The influence of the exchange-correlation functional (semilocal gradient corrected or hybrid functional) on density-functional studies of the adsorption of CO and NO in Cu- and Co-exchanged chabazite has been investigated, extending the studies of the structural and electronic properties of these ma ... [J. Chem. Phys. 136, 064503 (2012)] published Wed Feb 8, 2012.
Selective probe of the morphology and local vibrations at carbon nanoasperities
Toshihiko Fujimori (藤森&#x 5229;彦), Koki Urita (瓜田&#x 5E78;幾), David Tomanek, Tomonori Ohba (大場&#x 53CB;則), Isamu Moriguchi (森口&#x 52C7;) et al.
We introduce a way to selectively probe local vibration modes at nanostructured asperities such as tips of carbon nanohorns. Our observations benefit from signal amplification in surface-enhanced Raman scattering (SERS) at sites near a silver surface. We observe nanohorn tip vibration modes in the r ... [J. Chem. Phys. 136, 064505 (2012)] published Wed Feb 8, 2012.
Mesoscopic analysis of Gibbs' criterion for sessile nanodroplets on trapezoidal substrates
F. Dutka, M. Napiorkowski, and S. Dietrich
By taking into account precursor films accompanying nanodroplets on trapezoidal substrates we show that on a mesoscopic level of description one does not observe the phenomenon of liquid-gas-substrate contact line pinning at substrate edges. This phenomenon is present in a macroscopic description an ... [J. Chem. Phys. 136, 064702 (2012)] published Wed Feb 8, 2012.
The role of structure in the nonlinear mechanics of cross-linked semiflexible polymer networks
Nicholas Agung Kurniawan, Soren Enemark, and Raj Rajagopalan
The microstructural basis of the characteristic nonlinear mechanics of biopolymer networks remains unclear. We present a 3D network model of realistic, cross-linked semiflexible fibers to study strain-stiffening and the effect of fiber volume-occupancy. We identify two structural parameters, namely, ... [J. Chem. Phys. 136, 065101 (2012)] published Wed Feb 8, 2012.
A first-principles density functional theory study of the electronic structural and thermodynamic properties of MZrO and MCO (M = Na, K) and their capabilities for CO capture
Yuhua Duan
Alkali metal zirconates could be used as solid sorbents for CO capture. The structural, electronic, and phonon properties of NaZrO, KZrO, NaCO, and KCO are investigated by combining the density functional theory with lattice phonon dynamics. The thermodynamics of CO absorption/desorption reactions o ... [J. Renewable Sustainable Energy 4, 013109 (2012)] published Wed Feb 8, 2012.
Insulation and diffusion barrier characteristics of spin-on-glass layer on a stainless steel substrate
Ming-Jer Jeng, Wei-Jer Lai, Bai-Zong Chang, and Sung-Cheng Hu
The efficiency of CIGS (Copper Indium Gallium diSelenide) solar cells fabricated on stainless steel foil is lower than that on soda-lime glass substrates due to the lack of sodium incorporation and metal impurity diffusion. A dielectric barrier is necessary to prevent metal impurity diffusion for st ... [J. Renewable Sustainable Energy 4, 011603 (2012)] published Wed Feb 8, 2012.
Coexistence of bi-stable memory and mono-stable threshold resistance switching phenomena in amorphous NbO films
Jieun Bae, Inrok Hwang, Yuhyun Jeong, Sung-Oong Kang, Sahwan Hong et al.
Both bi-stable memory and mono-stable threshold switching are observed in amorphous NbO films. In addition, the transition between memory and threshold switching can be induced by changing external electrical stress. Raman spectroscopy and transmission electron microscope data show that the NbO film ... [Appl. Phys. Lett. 100, 062902 (2012)] published Wed Feb 8, 2012.
Spectral reflectance switching of colloidal photonic crystal structure composed of positively charged TiO nanoparticles
HongShik Shim, Joohyun Lim, Chang Gyun Shin, Seog-Jin Jeon, Moon Gyu Han et al.
We report the tunable photonic crystal behavior of highly concentrated, mildly charged TiO nanoparticle colloids under external electric field. Reflectance intensity change at the certain photonic bandgap and its irreversible switching characteristics are observed and discussed. Through computer aid ... [Appl. Phys. Lett. 100, 063113 (2012)] published Wed Feb 8, 2012.
High-pressure phases of NaAlH from first principles
Xiang-Feng Zhou (周向锋), Xiao Dong (董校), Zhisheng Zhao (赵智胜), Artem R. Oganov, Yongjun Tian (田永君) et al.
High-pressure phases of NaAlH are predicted using the ab initio evolutionary algorithm. our first-principles calculations reveal that the low-pressure I4/a phase containing AlH tetrahedra transforms into the monoclinic P2/c phase at 3.8 GPa and then into the orthorhombic Ima2 phase at 20.5 GPa. The ... [Appl. Phys. Lett. 100, 061905 (2012)] published Wed Feb 8, 2012.
Effect of surface plasmon energy matching on the sensing capability of metallic nano-hole arrays
Mohamadreza Najiminaini, Fartash Vasefi, Bozena Kaminska, and Jeffrey J. L. Carson
We report on a nano-hole array structure with a single cavity beneath the perforated gold film. Structures were fabricated with a variety of cavity depths. The optical resonance of each structure as well as the surface plasmon (SP) energy matching between the top and bottom of the gold film were inv ... [Appl. Phys. Lett. 100, 063110 (2012)] published Wed Feb 8, 2012.
Twin structures of epitaxial SnO films grown on a-cut sapphire by metalorganic chemical vapor deposition
Zhen Zhu, Jin Ma, Caina Luan, Wei Mi, and Yu Lv
SnO films have been grown on a-cut (11[overline 2]0) sapphire substrates by metalorganic chemical vapor deposition. X-ray diffraction and transmission electron microscopy were employed to characterize the epitaxial relationship and film structure. The films were (101) oriented with pure rutile struc ... [J. Vac. Sci. Technol. A 30, 021503 (2012)] published Wed Feb 8, 2012.
Weak Exciton Scattering in Molecular Nanotubes Revealed by Double-Quantum Two-Dimensional Electronic Spectroscopy
Darius Abramavicius, Alexandra Nemeth, Franz Milota, Jaroslaw Sperling, Shaul Mukamel et al.
The two-exciton manifold of a double-wall cylindrical molecular aggregate is studied using a coherent third order optical technique. Experiments reveal the anharmonic character of the exciton bands. Atomistic simulations of the exciton-exciton scattering show that the excitons can be treated as weak ... [Phys. Rev. Lett. 108, 067401 ] published .
Crystal Structure of Cold Compressed Graphite
Maximilian Amsler, Jose A. Flores-Livas, Lauri Lehtovaara, Felix Balima, S. Alireza Ghasemi et al.
Through a systematic structural search we found an allotrope of carbon with Cmmm symmetry which we predict to be more stable than graphite for pressures above 10 GPa. This material, which we refer to as Z-carbon, is formed by pure sp bonds and it provides an explanation to several features in experi ... [Phys. Rev. Lett. 108, 065501 ] published .
Effect of alcohol on single-bubble sonoluminescence
Weicheng Cui, Shuibao Qi, Weizhong Chen, Chao Zhou, and Juan Tu
The driving parametric regions in frequency-amplitude space and the optimal parameters for single-bubble sonoluminescence (SBSL) in alcohol aqueous solutions are studied systematically by taking measurements of the spectrum and bubble dynamics. The experimental results show that with an increase in ... [Phys. Rev. E 85, 026304 ] published .
Threshold of hierarchical percolating systems
Jiantong Li, Biswajit Ray, Muhammad A. Alam, and Mikael Ostling
Many modern nanostructured materials and doped polymers are morphologically too complex to be interpreted by classical percolation theory. Here, we develop the concept of a hierarchical percolating (percolation-within-percolation) system to describe such complex materials and illustrate how to gener ... [Phys. Rev. E 85, 021109 ] published .
Interwall screening and excitons in double-wall carbon nanotubes
Yuh Tomio, Hidekatsu Suzuura, and Tsuneya Ando
Exciton properties of double-wall carbon nanotubes are studied in the static screened Hartree-Fock approximation within a kp scheme. The intrawall electron-hole interaction is largely suppressed by interwall screening effects. The suppression is sensitive to the effective interwall distance between ... [Phys. Rev. B 85, 085411 ] published .
Lattice instability and elastic dispersion due to the rattling motion in the type-I clathrate BaGaSn
Isao Ishii, Yasuhiko Suetomi, Takahiro K. Fujita, Koichiro Suekuni, Tomoo Tanaka et al.
To investigate the off-center rattling motion and its charge-carrier dependence in type-I clathrate compounds, we carried out ultrasonic measurements on type-I BaGaSn and a reference compound, KGaSn. We found elastic softening of C originating from a lattice instability due to the off-center rattlin ... [Phys. Rev. B 85, 085101 ] published .
Number of observable features in the acoustic Raman spectra of nanocrystals
Lucien Saviot, Nicolas Combe, and Adnen Mlayah
Low-frequency Raman-scattering spectra are presented for gold nanocrystals with diameters 3.5 and 13 nm. The frequencies of the Raman peaks but also their number are shown to vary with the nanocrystal size. These results are analyzed using both the continuous elastic medium approximation and an atom ... [Phys. Rev. B 85, 075405 ] published .
Hole depletion of ladders in SrCuO induced by correlation effects
V. Ilakovac, C. Gougoussis, M. Calandra, N. B. Brookes, V. Bisogni et al.
The hole distribution in SrCuO is studied by low-temperature polarization-dependent O K near-edge x-ray absorption fine-structure measurements and state-of-the-art electronic structure calculations that include core-hole and correlation effects in a mean-field approach. Contrary to all previous anal ... [Phys. Rev. B 85, 075108 ] published .
Shear modulus of an elastic solid under external pressure as a function of temperature: The case of helium
Felipe Barra, Fernando Lund, Nicolas Mujica, and Sergio Rica
The energy of a dislocation loop in a continuum elastic solid under pressure is considered within the framework of classical mechanics. For a circular loop, this is a function with a maximum at pressures that are well within reach of experimental conditions for solid helium, suggesting, in this case ... [Phys. Rev. B 85, 064103 ] published .
Structure of a 2 (010) Cu twist boundary interface and the segregation of vacancies and He atoms
Enrique Martinez, John P. Hirth, Michael Nastasi, and Alfredo Caro
A 2 (010) Cu twist boundary is characterized by two sets of (1/2) screw dislocations crossing at misfit dislocation intersections (MDIs). Molecular dynamics simulations show that between MDIs, dislocations split into the two possible {111} planes that share the direction, forming a constriction whe ... [Phys. Rev. B 85, 060101 ] published .
First-principles calculation of phase equilibrium of V-Nb, V-Ta, and Nb-Ta alloys
C. Ravi, B. K. Panigrahi, M. C. Valsakumar, and Axel van de Walle
In this paper, we report the calculated phase diagrams of V-Nb, V-Ta, and Nb-Ta alloys computed by combining the total energies of 4050 configurations for each system (obtained using density functional theory) with the cluster expansion and Monte Carlo techniques. For V-Nb alloys, the phase diagram ... [Phys. Rev. B 85, 054202 ] published .
Fermi polarons in two dimensions
Richard Schmidt, Tilman Enss, Ville Pietila, and Eugene Demler
We theoretically analyze inverse radio-frequency (rf) spectroscopy experiments in two-component Fermi gases. We consider a small number of impurity atoms interacting strongly with a bath of majority atoms. In two-dimensional geometries we find that the main features of the rf spectrum correspond to ... [Phys. Rev. A 85, 021602 ] published .
ZnO/Si arrays decorated by Au nanoparticles for surface-enhanced Raman scattering study
Yu Fei Chan, Hai Jun Xu, Lei Cao, Ying Tang, De Yao Li et al.
Large scale and highly ordered flowerlike ZnO/Si nanostructures are successfully prepared by combining two common techniques, viz. hydrothermally etch fabrication of nanoporous Si pillar array (NSPA) and self-catalytic chemical vapor transport growth of ZnO nanowires. Au nanoparticles are decorated ... [J. Appl. Phys. 111, 033104 (2012)] published Tue Feb 7, 2012.
Mixed self-assembled monolayer of molecules with dipolar and acceptor characterInfluence on hysteresis and threshold voltage in organic thin-film transistors
Abdesselam Jedaa, Michael Salinas, Christof M. Jager, Timothy Clark, Alexander Ebel et al.
In this report, we investigate the impact of the molecular dipole moment and redox active head groups (C) in pure and mixed self-assembled monolayers (SAMs), which serve as an ultra-thin hybrid dielectric layer in low-voltage operating organic thin-film transistors. We show that the dipole of the SA ... [Appl. Phys. Lett. 100, 063302 (2012)] published Tue Feb 7, 2012.
Parabolic polarization splitting of Tamm states in a metal-organic microcavity
R. Bruckner, M. Sudzius, S. I. Hintschich, H. Frob, V. G. Lyssenko et al.
We observe hybrid states of cavity photons and Tamm plasmons in an organic microcavity with an incorporated thin silver layer of increasing thickness up to 40 nm. Via [mu]-photoluminescence spectroscopy, we investigate their angular dependence. At oblique angles, we observe a TE-TM polarization spli ... [Appl. Phys. Lett. 100, 062101 (2012)] published Tue Feb 7, 2012.
Sub-250 nm room-temperature optical gain from AlGaN/AlN multiple quantum wells with strong band-structure potential fluctuations
Emanuele Francesco Pecora, Wei Zhang, A. Yu. Nikiforov, Lin Zhou, David J. Smith et al.
Deep-UV optical gain has been demonstrated in AlGaN/AlN multiple quantum wells under femtosecond optical pumping. Samples were grown by molecular beam epitaxy under a growth mode that introduces band structure potential fluctuations and high-density nanocluster-like features within the AlGaN wells. ... [Appl. Phys. Lett. 100, 061111 (2012)] published Tue Feb 7, 2012.
Normalization schemes for ultrafast x-ray diffraction using a table-top laser-driven plasma source
D. Schick, A. Bojahr, M. Herzog, C. von Korff Schmising, R. Shayduk et al.
We present an experimental setup of a laser-driven x-ray plasma source for femtosecond x-ray diffraction. Different normalization schemes accounting for x-ray source intensity fluctuations are discussed in detail. We apply these schemes to measure the temporal evolution of Bragg peak intensities of ... [Rev. Sci. Instrum. 83, 025104 (2012)] published Tue Feb 7, 2012.
Search for a small hole in a cavity wall by intermittent bulk and surface diffusion
Alexander M. Berezhkovskii and Alexander V. Barzykin
We study the search of a small round hole in the wall of a spherical cavity by a diffusing particle, which can reversibly bind to the cavity wall and diffuse on the surface being in the bound state. There are two channels for the particle first passage to the hole, through the bulk, and through the ... [J. Chem. Phys. 136, 054115 (2012)] published Tue Feb 7, 2012.
Publisher's Note: Random sequential adsorption of partially oriented linear k-mers on a square lattice [Phys. Rev. E 84, 061603 (2011)]
Nikolai I. Lebovka, Natalia N. Karmazina, Yuri Yu. Tarasevich, and Valeri V. Laptev
Abstract not available. [Phys. Rev. E 85, 029902 ] published .
Semiconductor qubits based on fluorine implanted ZnMgSe/ZnSe quantum-well nanostructures
Y. M. Kim, D. Sleiter, K. Sanaka, Y. Yamamoto, J. Meijer et al.
It has been shown that the excitons bound to individual donors in epitaxially grown ZnMgSe/ZnSe quantum-well (QW) nanostructures provide suitable single-photon sources and optically controllable qubits for quantum information technology. Here we demonstrate ion implantation as an alternative fluorin ... [Phys. Rev. B 85, 085302 ] published .
Exciton acoustic-phonon coupling in single GaN/AlN quantum dots
Irina A. Ostapenko, Gerald Honig, Sven Rodt, Andrei Schliwa, Axel Hoffmann et al.
Coupling of acoustic phonons to excitons in single wurtzite-type GaN/AlN quantum dots is investigated in detail by cathodoluminescence experiments and compared to theory. Numerical simulations of the coupling in the framework of the independent Boson model with realistic wave functions based on 8-ba ... [Phys. Rev. B 85, 081303 ] published .
Capillary condensation, freezing, and melting in silica nanopores: A sorption isotherm and scanning calorimetry study on nitrogen in mesoporous SBA-15
Sebastian T. Moerz, Klaus Knorr, and Patrick Huber
Condensation, melting, and freezing of nitrogen in a powder of mesoporous silica grains (SBA-15) has been studied by combined volumetric sorption isotherm and scanning calorimetry measurements. Within the mean-field model of Saam and Cole for vapor condensation in cylindrical pores, a liquid nitroge ... [Phys. Rev. B 85, 075403 ] published .
Ionization of coherent excitons by strong terahertz fields
B. Ewers, N. S. Koster, R. Woscholski, M. Koch, S. Chatterjee et al.
The interaction of coherent excitons with intense, single-cycle terahertz (THz) pulses is investigated. A significant bleaching of the 1s-exciton resonance develops into a splitting of the absorption peak and the emergence of pronounced wings with increasing THz field strength. A quantum-mechanical ... [Phys. Rev. B 85, 075307 ] published .
Anisotropic surface coupling while sliding on dolomite and calcite crystals
Carlos M. Pina, Rodolfo Miranda, and Enrico Gnecco
High-resolution friction force microscopy has been performed on the (104) surfaces of dolomite and calcite in deionized water. The two rows of oxygen atoms alternating in a zigzag way on top of both surfaces are resolved with similar contrast while scanning along the [42[overline 1]] direction. Alon ... [Phys. Rev. B 85, 073402 ] published .
Size-induced melting and reentrant freezing in fullerene-doped helium clusters
F. Calvo
The structural and dynamical stabilities of CHe clusters are theoretically investigated using global optimization and path-integral simulation methods. Up to N=32, the fullerene ion traps the helium atoms onto sixfold and fivefold faces, strongly enough to negate vibrational delocalization. Above th ... [Phys. Rev. B 85, 060502 ] published .
Publisher's Note: Infrared optical response of LuFeO under dc electric field [Phys. Rev. B 85, 014303 (2012)]
Chul Lee, JooYoun Kim, S. W. Cheong, and E. J. Choi
Abstract not available. [Phys. Rev. B 85, 059902 ] published .
Static compression of LiH to 250 GPa
A. Lazicki, P. Loubeyre, F. Occelli, Russell J. Hemley, and M. Mezouar
The equation of state of LiH was extended to 252 GPa (V/V=32%) at room temperature using x-ray diffraction in diamond-anvil cells. LiH was shown to remain in the the NaCl (B1) structure under these conditions, and the predicted B1-B2 phase transition well known in neighboring alkali halides was not ... [Phys. Rev. B 85, 054103 ] published .
Phase diagram of Landau-Zener phenomena in coupled one-dimensional Bose quantum fluids
Santiago F. Caballero-Benitez and Rosario Paredes
We study stationary and dynamical properties of the many-body Landau-Zener dynamics of a Bose quantum fluid confined in two coupled one-dimensional chains by using a many-body generalization recently reported Chen et al. [Nature Phys. 7, 61 (2011)], within the decoupling approximation and the one-le ... [Phys. Rev. A 85, 023605 ] published .
Na incorporation into Cu(In,Ga)Se thin-film solar cell absorbers deposited on polyimide: Impact on the chemical and electronic surface structure
X. Song, R. Caballero, R. Felix, D. Gerlach, C. A. Kaufmann et al.
Na has deliberately been incorporated into Cu(In,Ga)Se (CIGSe) chalcopyrite thin-film solar cell absorbers deposited on Mo-coated polyimide flexible substrates by adding differently thick layers of NaF in-between CIGSe absorber and Mo back contact. The impact of Na on the chemical and electronic sur ... [J. Appl. Phys. 111, 034903 (2012)] published Mon Feb 6, 2012.
The effect of In-flush on the optical anisotropy of InAs/GaAs quantum dots
M. Molas, K. Golasa, K. Kuldova, J. Borysiuk, A. Babinski et al.
The effect of the In-flush technique on the optical anisotropy of InAs/GaAs quantum dots (QDs) has been investigated. The anisotropy was deduced from low temperature microluminescence measurements of the splitting of the emission lines related to single neutral excitons confined to the QDs. It was f ... [J. Appl. Phys. 111, 033510 (2012)] published Mon Feb 6, 2012.
Interfaces between nonpolar and semipolar III-nitride semiconductor orientations: Structure and defects
J. Kioseoglou, A. Lotsari, E. Kalesaki, and G. P. Dimitrakopulos
Observations of easy transition between nonpolar and semipolar orientations during III-Nitride heteroepitaxy identify the 90 <[overline 1]2[overline 1]0> rotation relationship as being very important in defining this coexistence. A rigorous analysis of this relationship using the topological theory ... [J. Appl. Phys. 111, 033507 (2012)] published Mon Feb 6, 2012.
The study of pressure induced structural phase transition in spin-frustrated YbTiO pyrochlore
A. K. Mishra, H. K. Poswal, Surinder M. Sharma, Surajit Saha, D. V. S. Muthu et al.
Our in situ x-ray diffraction and Raman measurements of YbTiO pyrochlore show that it undergoes a reversible structural phase transition from cubic pyrochlore to a monoclinic phase at ~28.6 GPa. Analysis of the x-ray data shows the transition to be thermodynamically first order and the high pressure ... [J. Appl. Phys. 111, 033509 (2012)] published Mon Feb 6, 2012.
Sound velocity measurements of tantalum under shock compression in the 10-110 GPa range
Jianbo Hu, Chengda Dai, Yuying Yu, Zijiang Liu, Ye Tan et al.
The high-pressure melting curve of tantalum (Ta) has been the center of a long-standing controversy. Sound velocities along the Hugoniot curve are expected to help in understanding this issue. To that end, we employed a direct-reverse impact technique and velocity interferometry to determine sound v ... [J. Appl. Phys. 111, 033511 (2012)] published Mon Feb 6, 2012.
Spontaneous induction of the uniform lying helix alignment in bimesogenic liquid crystals for the flexoelectro-optic effect
Damian J. Gardiner, Stephen M. Morris, Philip J. W. Hands, Flynn Castles, Malik M. Qasim et al.
Using in-plane electric fields, the electrical induction of the uniform lying helix (ULH) alignment in chiral nematic liquid crystals is reported. This process permits spontaneous induction of the ULH alignment to give an in-plane optic axis, without the need for complex processing. Flexoelectro-opt ... [Appl. Phys. Lett. 100, 063501 (2012)] published Mon Feb 6, 2012.
Oxygen vacancy segregation and space-charge effects in grain boundaries of dry and hydrated BaZrO
B. Joakim Nyman, Edit E. Helgee, and Goran Wahnstrom
A space-charge model is applied to describe the equilibrium effects of segregation of double-donor oxygen vacancies to grain boundaries in dry and wet acceptor-doped samples of the perovskite oxide BaZrO. The grain boundary (GB) core vacancy concentrations and electrostatic potential barriers result ... [Appl. Phys. Lett. 100, 061903 (2012)] published Mon Feb 6, 2012.
Formation of dodecagonal quasicrystals in two-dimensional systems of patchy particles
Marjolein N. van der Linden, Jonathan P. K. Doye, and Ard A. Louis
The behaviour of two-dimensional patchy particles with five and seven regularly arranged patches is investigated by computer simulation. For higher pressures and wider patch widths, hexagonal crystals have the lowest enthalpy, whereas at lower pressures and for narrower patches, lower density crysta ... [J. Chem. Phys. 136, 054904 (2012)] published Mon Feb 6, 2012.
Elastic and plastic anisotropy after straining of nanocrystalline palladium
D. V. Bachurin and P. Gumbsch
Atomistic simulations of uniaxial straining of three-dimensional nanocrystalline palladium along different loading paths were performed at room temperature and at a constant strain rate of 10 s. It is found that both the elastic behavior and plastic behavior of the specimen display a pronounced anis ... [Phys. Rev. B 85, 085407 ] published .
Nonadiabatic switching of a photonic band structure: Ultrastrong light-matter coupling and slow-down of light
M. Porer, J.-M. Menard, A. Leitenstorfer, R. Huber, R. Degl'Innocenti et al.
We map out the band structure of a one-dimensional photonic crystal while a 12-fs control pulse activates ultrastrong interaction with quantized electronic transitions in semiconductor quantum wells. Phase-locked multi-terahertz transients trace the buildup of a large vacuum Rabi splitting and an un ... [Phys. Rev. B 85, 081302 ] published .
Ultrafast pump-probe measurements of short small-polaron lifetimes in the mixed-valence perovskite CsAuI under high pressures
M. Trigo, J. Chen, M. P. Jiang, W. L. Mao, S. C. Riggs et al.
We study the ultrafast phonon response of mixed-valence perovskite CsAuI using pump-probe spectroscopy under high pressure in a diamond-anvil cell. We observed a remarkable softening and broadening of the Au-I stretching phonon mode with both applied pressure and photoexcitation. Using a double-pump ... [Phys. Rev. B 85, 081102 ] published .
Variable group delay in a metamaterial with field-gradient-induced transparency
Yasuhiro Tamayama, Toshihiro Nakanishi, and Masao Kitano
We realize variable control of the group delay in an electromagnetically induced transparency-like metamaterial. Its unit cell is designed to have a bright mode and a dark mode. The coupling strength between these two modes is determined by the electromagnetic field gradient. In this metamaterial wi ... [Phys. Rev. B 85, 073102 ] published .
Quasiclassical and ultraquantum decay of superfluid turbulence
A. W. Baggaley, C. F. Barenghi, and Y. A. Sergeev
We address a question which, after a decade-long discussion, still remains open: what is the nature of the ultraquantum regime of decay of quantum turbulence? The model developed in this work reproduces both the ultraquantum and the quasiclassical decay regimes and explains their hydrodynamical natu ... [Phys. Rev. B 85, 060501 ] published .