ELECTRON–PHONON INTERACTION IN WURTZITE AlxGa1-xN TERNARY CRYSTAL

2007 ◽  
Vol 21 (22) ◽  
pp. 3841-3850 ◽  
Author(s):  
SHU YI WEI ◽  
FANG ZHANG ◽  
WEI LI ◽  
ZU ZHAO ◽  
WEN DENG HUANG
Keyword(s):  
Unit Cell Volume ◽  
Unit Cell ◽  
Coupling Constants ◽  
Phonon Interaction ◽  
Electron Phonon Interaction ◽  
Effective Masses ◽  
Mode Behavior ◽  
Polaron Energy ◽  
The One ◽  
Ternary Nitride

Optical vibrations of the lattice and the electron-optical-phonon interaction in wurtzite ternary nitride-based crystals was studied using the pseudo-unit-cell approach. The Fröhlich coupling constants, polaron energy shifts and the effective masses of the polaron in the system were investigated using the perturbation method. It was found that the LO and TO phonons in wurtzite Al x Ga 1-x N exhibit the one-mode behavior. The effects of the unit-cell volume varying with the composition x of ternary nitride-based crystals were also investigated.

THE REFLECTIVITY OF THE MIXED CRYSTAL AB1-xCx

2010 ◽  
Vol 24 (27) ◽  
pp. 5337-5343
Author(s):  
XIAOYAN ZHANG ◽  
JINGFENG WANG ◽  
GUOLIANG FAN
Keyword(s):  
Mixed Crystal ◽  
Random Element ◽  
Mixed Crystals ◽  
Phonon Interaction ◽  
Long Wavelength ◽  
Electron Phonon Interaction ◽  
The Third ◽  
Optical Character ◽  
Mode Behavior ◽  
The One

The properties of long wavelength optical phonons in mixed crystals AB 1-x C x is discussed by a model similar to Modified Random Element Isodisplacement (MREI). Using this method we investigate the frequencies, the dielectric functions, and the reflectivity of several mixed crystals. It is found that this model can be applied to the one-mode behavior, the two-mode behavior, and that of the third category. So the model provides a possible way to understand the optical character of the ternary mixed crystal. Based on it, we can discuss other problems similar to electron–phonon interaction and so on.

Electron–phonon interaction in three-, two- and one-dimensional ternary mixed crystals

2016 ◽  
Vol 30 (15) ◽  
pp. 1650182
Author(s):  
Junhua Hou ◽  
Yunpeng Fan
Keyword(s):  
Cell Volume ◽  
Effective Mass ◽  
Unit Cell Volume ◽  
Three Dimensional ◽  
Unit Cell ◽  
Mixed Crystals ◽  
Phonon Interaction ◽  
One Dimensional ◽  
Electron Phonon Interaction ◽  
Self Trapping

The electron–phonon (e–p) interaction in three-dimensional (3D), two-dimensional (2D) and one-dimensional (1D) ternary mixed crystals is studied. The e–p interaction Hamiltonians including the unit cell volume variation in ternary mixed crystals are obtained by using the modified random-element-isodisplacement model and Born–Huang method. The polaronic self-trapping energy and renormalized effective mass of GaAs[Formula: see text]Sb[Formula: see text], GaP[Formula: see text]As[Formula: see text] and GaP[Formula: see text]Sb[Formula: see text] compounds are numerically calculated. It is confirmed theoretically that the nonlinear variation of the self-trapping energy and effective mass with the composition is essential and the unit cell volume effects cannot be neglected except the weak e–p coupling. The dimensional effect cannot also be ignored.

Electron–phonon interaction in quasi-1D ternary mixed crystals of polar semiconductors

2015 ◽  
Vol 29 (23) ◽  
pp. 1550130 ◽  
Author(s):  
Yunpeng Fan ◽  
Junhua Hou
Keyword(s):  
Cell Volume ◽  
Unit Cell Volume ◽  
Mixed Crystal ◽  
Random Element ◽  
Unit Cell ◽  
Mixed Crystals ◽  
Phonon Modes ◽  
Phonon Interaction ◽  
One Dimensional ◽  
Electron Phonon Interaction

The electron–optical-phonon interaction between an electron and two branches of LO-phonon modes in a quasi-one-dimensional ternary mixed crystal (TMC) of polar semiconductors is studied. The new electron–phonon interaction Hamiltonian including the unit-cell volume variation in TMCs is obtained by using the modified random element isodisplacement model and Born–Huang method. The energies of polaron are numerically calculated for several systems of III–V compounds. A group of III-nitride mixed crystals is also taken into numerical calculation in our theory. It is verified theoretically that the obvious nonlinearity of the polaronic energy and effective mass with the composition is essential and the unit-cell volume effects cannot be neglected except the very weak e–p coupling.

ELECTRONIC THEORY FOR ELECTRON-DOPED CUPRATE SUPERCONDUCTORS: d-WAVE SUPERCONDUCTIVITY AND THE PHASE DIAGRAM

2000 ◽  
Vol 14 (29n31) ◽  
pp. 3555-3560
Author(s):  
D. MANSKE ◽  
I. EREMIN ◽  
K. H. BENNEMANN
Keyword(s):  
Cuprate Superconductors ◽  
Narrow Range ◽  
Spin Fluctuation ◽  
Flat Band ◽  
Superconducting Transition ◽  
Phonon Interaction ◽  
Pairing Mechanism ◽  
Lattice Disorder ◽  
Electron Phonon Interaction ◽  
The One

Using the one-band Hubbard Hamiltonian we determine various basic properties of the electron-doped cuprate superconductor Nd 2-x Ce x CuO 4 for a spin-fluctuation-induced pairing mechanism. We find a narrow range of superconductivity and, most importantly, like for hole-doped cuprates dx2-y2 -symmetry for the superconducting order parameter. The superconducting transition temperatures Tc(x) for various electron doping concentrations x are calculated to be much smaller than for hole-doped cuprates due to the different energy dispersion and a flat band well below the Fermi level. We find that lattice disorder may sensitively distort the dx2-y2 -symmetry via electron-phonon interaction yielding a finite isotope exponent α0.

Hot Electrons Relaxation

1990 ◽  
Vol 209 ◽  
Author(s):  
A.M. Mazzone
Keyword(s):  
Simulation Method ◽  
High Energy ◽  
Hot Electrons ◽  
Direct Simulation ◽  
Thermal Spike ◽  
Phonon Interaction ◽  
Lattice Disorder ◽  
Electron Phonon Interaction ◽  
Quantum Mechanical Representation ◽  
The One

ABSTRACTThis work represents the first attempt of a direct simulation of the processes of electron-phonon interaction and lattice excitation which follow the formation of an excited electron gas such as, for instance, is the one produced by high-energy implants. The simulation method is of the type molecular dynamics and is based on a quantum mechanical representation. The results suggest a lattice disorder similar to the one of a thermal spike.

scholarly journals Measuring the Electron–Phonon Interaction in Two-Dimensional Superconductors with He-Atom Scattering

2020 ◽  
Vol 5 (4) ◽  
pp. 79
Author(s):  
Giorgio Benedek ◽  
Joseph R. Manson ◽  
Salvador Miret-Artés ◽  
Adrian Ruckhofer ◽  
Wolfgang E. Ernst ◽  
...  
Keyword(s):  
Enhancement Factor ◽  
Coupling Constants ◽  
Phonon Coupling ◽  
Phonon Interaction ◽  
Helium Atom Scattering ◽  
Electron Phonon Interaction ◽  
Atom Scattering ◽  
Electron Phonon Coupling ◽  
Layered Transition Metal ◽  
Mass Enhancement

Helium-atom scattering (HAS) spectroscopy from conducting surfaces has been shown to provide direct information on the electron–phonon interaction, more specifically the mass-enhancement factor λ from the temperature dependence of the Debye–Waller exponent, and the mode-selected electron–phonon coupling constants λQν from the inelastic HAS intensities from individual surface phonons. The recent applications of the method to superconducting ultra-thin films, quasi-1D high-index surfaces, and layered transition-metal and topological pnictogen chalcogenides are briefly reviewed.

Theory of Phonon Induced Anisotropy in h.c.p. Metals: Zn

1973 ◽  
Vol 51 (9) ◽  
pp. 922-937 ◽  
Author(s):  
P. T. Truant ◽  
J. P. Carbotte
Keyword(s):  
Numerical Results ◽  
Unit Cell ◽  
Induced Anisotropy ◽  
Superconducting Properties ◽  
Mass Renormalization ◽  
Phonon Interaction ◽  
Pseudopotential Theory ◽  
Electron Phonon Interaction ◽  
Self Energy ◽  
Von Karman

We present a formulation of the electron–phonon interaction which applies to the case of two atoms per unit cell. Realistic Born–von Kármán phonons are used and the electron–ion interaction is treated in pseudopotential theory. Detailed numerical results are presented for the specific case of Zn. The electron–phonon function α2(ω)F(ω) which enters the electron self-energy and the superconducting properties is calculated. Associated directional functions which allow a discussion of the anisotropy in the electron–phonon interaction are also given. They are employed in a discussion of the anisotropy that enters the electron–phonon mass renormalization as well as scattering times.

DIFFERENCE OF VARIATION OF UNIT CELL VOLUME V AND Tc WITH OXYGEN CONTENT IN YBa2Cu3O7−x AND LaBa2Cu3O7+x

1988 ◽  
Vol 02 (03n04) ◽  
pp. 641-650
Author(s):  
G.C. CHE ◽  
S.S. XIE ◽  
J.K. LIANG ◽  
K.S. LI ◽  
D.N. ZHENG ◽  
...  
Keyword(s):  
Cell Volume ◽  
Oxygen Content ◽  
Unit Cell Volume ◽  
Lattice Parameter ◽  
Unit Cell ◽  
Dimensional Chain ◽  
One Dimensional ◽  
The One

In YBa 2 Cu 3 O 7−x, the more the oxygen content is the higher is the Tc, the smaller is the lattice parameter c and the unit cell volume V. But in LaBa 2 Cu 3 O 7+x the less the oxygen content is, the higher is the Tc, the larger are c and V. These may be due to oxygen content being less than 7.0 in YBa 2 Cu 3 O 7−x and more than 7.0 in LaBa 2 Cu 3 O 7+x. These results give some informations regarding superconducting mechanism and show that the one-dimensional chain plays an important role.

Current Fluctuations of Hot Electrons

1970 ◽  
Vol 25 (7) ◽  
pp. 1107-1115 ◽  
Author(s):  
A. Friedmann ◽  
A. B. Fazakas
Keyword(s):  
Relaxation Time ◽  
External Field ◽  
The Other ◽  
Hot Electrons ◽  
Current Fluctuations ◽  
Phonon Interaction ◽  
Electrical Field ◽  
Electron Phonon Interaction ◽  
Electron Density Matrix ◽  
The One

In order to calculate the spectral density of current fluctuations in a high d. c. electrical field, a method using the one-electron density matrix is proposed. The nonperturbed problem is considered to be that of the electrons in an external field. The other interactions of electrons are expressed by means of a relaxation time matrix. To fit the expression of the current, given by the Boltzmannian formalism, a form of the diagonal terms of this matrix for electron-phonon interaction is suggested and closed formulae for the current fluctuations spectrum are obtained

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