Browsing by Keywords "Phonons"
Now showing items 1-20 of 57
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Anharmonicity in GaTe layered crystals
(Wiley-VCH Verlag GmbH & Co. KGaA, 2002)The temperature dependencies (10-300 K) of seven Raman-active mode frequencies in layered semiconductor gallium telluride have been measured in the frequency range from 25 to 300 cm -1. Softening and broadening of the ... -
Anharmonicity of zone-center optical phonons: Raman scattering spectra of GaSe0.5S0.5 layered crystal
(IOPscience, 2002)The temperature dependencies (10-300 K) of the eight Raman-active mode frequencies and linewidths in GaSe0.5S0.5 layered crystal have been measured in the frequency range from 10 to 320 cm-1. We observed softening and ... -
Characterization and stability of Janus TiXY (X/Y = S, Se, and Te) monolayers
(American Chemical Society, 2019)The realization of Janus MoSSe monolayers has brought two-dimensional (2D), ternary transition metal dichalcogenides (TMDs) into focus. The addition of a third element can lead to superior properties, hence extensive ... -
Confined optical phonon effects on the band gap renormalization in quantum wire structures
(Elsevier Science, 1999)We consider the different approximations for the bandgap renormalization (BGR) within the random phase approximation (RPA), the quasi-static limit and the plasmon-pole approximation, and compare with the full result. We ... -
Dynamical screening effects in hot-electron scattering from electron-hole plasma and LO-phonon modes in quantum wires
(Elsevier, 1996)We present a fully dynamical and finite temperature study of the hot-electron momentum relaxation rate and the power loss in a coupled system of electron-hole plasma and bulk LO-phonons in a quantum wire structure. ... -
Effects of anisotropy on the critical temperature in layered nonadiabatic superconductors
(Elsevier Science B.V., 2003)The generalized anisotropic Eliashberg theory is employed to study the critical temperature of layered nonadiabatic superconductors where the relevant phonon energy is comparable to the Fermi energy. We consider a ... -
Energy and mass of 3D and 2D polarons in the overall range of the electron-phonon coupling strength
(Institute of Physics Publishing Ltd., 1994)The ground-state characterization of the polaron problem is retrieved within the framework of a variational scheme proposed previously by Devreese et al for the bound polaron. The formulation is based on the standard ... -
Energy relaxation probed by weak antilocalization measurements in GaN heterostructures
(2009)Energy relaxation and electron-phonon (e-p) interaction are investigated in wurtzite Al0.15Ga0.85 N/AlN/GaN and Al0.83 In0.17 N/AlN/GaN heterostructures with polarization induced two-dimensional electron gases in the ... -
Existence of a metallic phase in a 1D Holstein-Hubbard model at half filling
(Elsevier B.V., 2007)The one-dimensional half-filled Holstein-Hubbard model is studied using a series of canonical transformations including phonon coherence effect that partly depends on the electron density and is partly independent and also ... -
First Principles Study of Barium Chalcogenides
(2008)In this study, ab initio calculation results of the vibrational properties and elastic parameters as well as characteristic Debye temperature and Poisson's ratios of two barium chalcogenides, BaSe and BaS, which crystallize ... -
Formation of Ge nanocrystals and SiGe in PECVD grown SiNx: Ge thin films
(Elsevier, 2006)Formation of Ge nanocrystals in SiNx matrices has been studied using plasma enhanced chemical vapor deposition in both as deposited samples as well as in post-vacuum annealed samples. Low temperature and short duration ... -
Hartree-Fock approximation of bipolaron state in quantum dots and wires
(Springer, 2010)The bipolaronic ground state of two electrons in a spherical quantum dot or a quantum wire with parabolic boundaries is studied in the strong electron-phonon coupling regime. We introduce a variational wave function that ... -
High-energy electron relaxation and full-band electron dynamics in aluminium nitride
(Elsevier, 2002)Material properties of AlN, particularly its wide band gap around 6 eV, warrant its operation in the high-field transport regimes reaching MV/cm fields. In this theoretical work, we examine the full-band scattering of ... -
Hybrid plasmon-phonon polariton bands in graphene-hexagonal boron nitride metamaterials [Invited]
(Optical Society of America, 2017)We theoretically investigate mid-infrared electromagnetic wave propagation in multilayered graphene-hexagonal boron nitride (hBN) metamaterials. Hexagonal boron nitride is a natural hyperbolic material that supports highly ... -
Hydrodynamic approach for modelling transport in quantum well device structures
(Institute of Physics Publishing Ltd., 1998)A semiclassical approach for modelling electron transport in quantum well structures is presented. The model is based on the balance equations governing the conservation of particle density, momentum and energy with Monte ... -
Isotope Effect and Phonon Softening in Superconducting Borocarbides and Boronitrides
(1998)The isotope effect in the recently disvovered class o superconductors LuNi2B2C and La3Ni2B2N3 is investigated in the context of electron-squezed phonon interaction renormalizing the Ni-d electron-electron correlations. ... -
Lattice dynamics and elastic properties of lanthanum monopnictides
(2008)In this study, first principles calculation results of the second order elastic constants and lattice dynamics of two lanthanum monopnictides, LaN and LaBi, which crystallize in rock-salt structure (B1 phase), are presented. ... -
Local-pair superconductivity in very high magnetic fields
(Scientific and Technical Research Council of Turkey - TUBITAK,Turkiye Bilimsel ve Teknik Arastirma Kurumu, 1996)Superconductivity of narrow-band systems with local, short-range attractive interaction in very high magnetic fields is discussed. By examining the excitation spectra of both type-II superconductors with BCS like interaction ... -
Low-temperature phase transitions in TlGaS2 layer crystals
(Pergamon Press, 1993)Polarized Raman scattering spectra of TlGaS2 layer crystals have been studied for the first time as a function of temperature between 8.5 and 295 K. No evidence for a soft mode behaviour has been found. The anomalies ... -
Magnetic field effects on an electron near an impenetrable dielectric surface
(1996)The interaction of an extrinsic electron with the surface optical modes of a semi-infinite medium is retrieved under the effect of a weak magnetic field. It is observed that for an electron in a bound state near the surface, ...
