scholarly journals Многократное изменение электрон-фононного взаимодействия в квантовых ямах с диэлектрически различными барьерами

2022 ◽  
Vol 56 (1) ◽  
pp. 101
Author(s):  
А.Ю. Маслов ◽  
О.В. Прошина
Keyword(s):  
Quantum Wells ◽  
Charged Particles ◽  
Strong Interactions ◽  
Asymmetric Structure ◽  
Optical Phonons ◽  
Phonon Modes ◽  
Phonon Interaction ◽  
Barrier Materials ◽  
Electron Phonon Interaction ◽  
Order Of Magnitude

Abstract The specific features of the interaction of charged particles with polar optical phonons have been studied theoretically for quantum wells with the barriers that are asymmetric in their dielectric properties. It is shown that the interaction with interface phonon modes makes the greatest contribution in narrow quantum wells. The parameters of the electron-phonon interaction were found for the cases of different values of the phonon frequencies in the barrier materials. It turned out that a significant (by almost an order of magnitude) change in the parameters of the electron-phonon interaction can occur in such structures. This makes it possible, in principle, to trace the transition from weak to strong interactions in quantum wells of the same type but with different compositions of barrier materials. The conditions are found under which an enhancement of the electron-phonon interaction is possible in an asymmetric structure in comparison with a symmetric one with the barriers of the same composition.

ELECTRIC FIELD EFFECTS ON POLARONS WITH SPATIALLY DEPENDENT MASS IN PARABOLIC QUANTUM WELLS

2004 ◽  
Vol 18 (22) ◽  
pp. 2991-2999 ◽  
Author(s):  
FENG-QI ZHAO ◽  
ZI-ZHENG GUO
Keyword(s):  
Electric Field ◽  
Quantum Wells ◽  
Effective Mass ◽  
Energy Levels ◽  
Longitudinal Optical ◽  
Optical Phonons ◽  
Phonon Interaction ◽  
Electron Phonon Interaction ◽  
Dependent Mass ◽  
Parabolic Quantum Wells

The free polaron energy levels in finite GaAs / Al x Ga 1-x As parabolic quantum wells have been investigated by a modified variational method. The effect of the electric field, the electron-phonon interaction including the longitudinal optical phonons and the four branches of interface optical phonons, and the effect of spatial dependent effective mass have been considered in the calculation. The dependence of the energies of free polarons on the alloy composition x is given. The numerical results for finite GaAs / Al x Ga 1-x As parabolic quantum wells are obtained and discussed. The results show that the effect of the electric field and the interface optical phonons as well as the longitudinal optical phonons on the energy levels is obvious. One can find that the effect of the spatially dependent effective masses on the energy levels in finite parabolic quantum wells is considerable except for large well width. Thus, the electron-phonon interaction and the effect of the spatially dependent effective mass should not be neglected for the study of the electron state problem in finite parabolic quantum wells.

scholarly journals Электрон-фононное взаимодействие в квантовых ямах на основе одноосных материалов

2019 ◽  
Vol 53 (12) ◽  
pp. 1641
Author(s):  
А.Ю. Маслов ◽  
О.В. Прошина
Keyword(s):  
Quantum Wells ◽  
Charged Particles ◽  
Optical Phonons ◽  
Coupling Constant ◽  
Strong Electron ◽  
Cubic Symmetry ◽  
Quantum Nanostructures ◽  
Electron Phonon Interaction ◽  
Degree Of Anisotropy ◽  
Type Coupling

AbstractThe interaction of charged particles with interface optical phonons in quantum wells composed of uniaxially symmetric materials is studied theoretically. It is shown that the character of this interaction depends considerably on the degree of anisotropy of the phonon spectrum in the materials forming the quantum well and the barriers. In the case of strong anisotropy, the interaction turns out to be significantly weaker than it is in similar structures made of materials with cubic symmetry. In the case of weak phonon anisotropy, the interaction of charged particles with optical phonons can under certain conditions be described by a Fröhlich-type coupling constant, and both weak and strong electron–phonon interaction can take place in different structures. The results obtained extend the possibilities of the optical diagnostics of quantum nanostructures.

Study of electron-phonon interaction in quantum wells using optically excited nonequilibrium population of phonons

1993 ◽  
Vol 13 (2) ◽  
pp. 203 ◽  
Author(s):  
Tobias Ruf ◽  
Keith Wald ◽  
Peter Y. Yu ◽  
K.T. Tsen ◽  
H. Morkoç ◽  
...  
Keyword(s):  
Quantum Wells ◽  
Phonon Interaction ◽  
Electron Phonon Interaction

POLAR VIBRATION SPECTRA OF INTERFACE AND SURFACE OPTICAL PHONONS AND THEIR FRÖHLICH ELECTRON-PHONON INTERACTIONS IN FREESTANDING SYMMETRICAL AND ASYMMETRICAL WURTZITEGaN/Ga1-xAlxNMULTI-LAYER HETEROSTRUCTURES

2006 ◽  
Vol 20 (05) ◽  
pp. 559-578 ◽  
Author(s):  
LI ZHANG ◽  
JUN-JIE SHI
Keyword(s):  
Quantum Wells ◽  
Electrostatic Potential ◽  
Uniaxial Crystal ◽  
Wave Number ◽  
Phonon Modes ◽  
Electron Phonon Interaction ◽  
Surface Optical ◽  
Electron Phonon Coupling ◽  
Crystal Model ◽  
Dielectric Continuum

Under the dielectric continuum model and Loudon's uniaxial crystal model, by adopting the transfer matrix method, the dispersion properties of the interface optical (IO) and surface optical (SO) phonon modes and their couplings with electrons in multi-layer coupling wurtzite quantum wells (QWs) are deduced and analyzed via the method of electrostatic potential expanding. Numerical calculations on a freestanding symmetrical wurtzite QW and an asymmetrical wurtzite QW have been performed. Results reveal that, in general, there are four branches of IO and two branches of SO phonon modes in the systems. The dispersions of these IO and SO phonon modes are obvious only when the free two-dimensional phonon wave number ktparallel to the heterostructure interfaces is small. The degenerating behavior for these phonon modes has been clearly observed for small kt. When ktis relatively large, with the increase in kt, the frequencies of the IO and SO phonon modes converge to some definite limiting frequencies in corresponding wurtzite single planar heterostructure. This feature have been analyzed in depth from the mathematical and physical viewpoints. The calculations of electron-phonon coupling function show that, the electrostatic potential distribution of the IO and SO mode in freestanding symmetrical wurtzite QW is either symmetrical or is antisymmetrical; but that in freestanding asymmetrical wurtzite QW is neither symmetrical nor is antisymmetric. The calculation also shows that the SO modes and the short wavelength phonon modes play a more important role in the electron-phonon interaction.

ELECTRON-PHONON INTERACTION AND SUPERCONDUCTIVITY IN OXIDE SUPERCONDUCTORS La2−xSrxCuO4

1993 ◽  
Vol 07 (01n03) ◽  
pp. 182-185
Author(s):  
M. SHIRAI ◽  
T. KINOSHITA ◽  
K. MOTIZUKI
Keyword(s):  
Tight Binding ◽  
Wide Energy Range ◽  
Oxide Superconductors ◽  
Tunneling Conductance ◽  
Eliashberg Equations ◽  
Phonon Modes ◽  
Phonon Interaction ◽  
Characteristic Structure ◽  
Electron Phonon Interaction ◽  
Wide Energy

Effects of electron-phonon interaction on lattice dynamics in oxide superconductors La 2−x Sr x CuO 4 (LSC) are studied microscopically on the basis of the tight-binding band fitted to the first principle band. Breathing-type vibrations of oxygen atoms in the CuO 2 plane are renormalized significantly at around (π/a, π/a, 0) and (π/a, 0, 0) due to strong dependences of the electron-phonon interaction on wavevectors and phonon modes. In the framework of the usual phonon-mediated pairing mechanism, superconducting properties, such as transition temperatures and tunneling spectra, are studied by solving isotropic Eliashberg equations. The spectral function α2F(ω) has a characteristic structure over a wide energy range below 85 meV. The tunneling conductance d I/ d V and its derivative d 2I/ d V2 calculated have prominent peaks below 40 meV, which show good correspondences to those observed by recent tunneling experiments.

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