scholarly journals Solutions of the Bogoliubov–de Gennes equation with position dependent Fermi-velocity and gap profiles

2017 ◽  
Vol 381 (7) ◽  
pp. 713-719
Author(s):  
M. Presilla ◽  
O. Panella ◽  
P. Roy
Keyword(s):  
Fermi Velocity ◽  
Gennes Equation

ON THE OPTICAL POTENTIAL OF AN ATTRACTIVE NONRELATIVISTIC DEGENERATE ELECTRON GAS INTERACTING WITH NUCLEAR MATTER

2012 ◽  
Vol 26 (31) ◽  
pp. 1250210 ◽  
Author(s):  
M. A. GRADO-CAFFARO ◽  
M. GRADO-CAFFARO
Keyword(s):  
Nuclear Matter ◽  
Optical Potential ◽  
Electron Gas ◽  
Three Dimensional ◽  
Harmonic Oscillators ◽  
Fermi Velocity ◽  
Potential Well ◽  
Schwinger Model ◽  
Degenerate Fermi Gas ◽  
Degenerate Electron Gas

The optical potential of an attractive nonrelativistic electron gas interacting with nuclear matter is determined on the basis of the concept of degenerate Fermi gas. In fact, the involved electrons are treated as three-dimensional quantum harmonic oscillators confined at the surface of a spherical (approximately ideal) potential well. Within this picture, the Fermi velocity is calculated as well as the spatial electron density at the surface of the potential well and the attractive force between the electron gas and the nuclear matter. In addition, considerations related to the Lippmann–Schwinger model are made.

Resonance of the Fermi velocity in weakly doped graphene

JETP Letters ◽  
2011 ◽  
Vol 94 (7) ◽  
pp. 565-569 ◽  
Author(s):  
Yu. V. Skrypnyk ◽  
V. M. Loktev
Keyword(s):  
Fermi Velocity ◽  
Doped Graphene

scholarly journals Superconducting coherence length of hole-doped cuprates obtained from electron–boson spectral density function

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jungseek Hwang
Keyword(s):  
Spectral Density ◽  
Coherence Length ◽  
Cooper Pair ◽  
Average Frequency ◽  
Spin Fluctuations ◽  
Fermi Velocity ◽  
Cooper Pairs ◽  
Spectroscopic Techniques ◽  
Microscopic Mechanism ◽  
Superconducting Coherence Length

AbstractElectron–boson spectral density functions (EBSDFs) can be obtained from measured spectra using various spectroscopic techniques, including optical spectroscopy. EBSDFs, known as glue functions, are suggested to have a magnetic origin. Here, we investigated EBSDFs obtained from the measured optical spectra of hole-doped cuprates with wide doping levels, from underdoped to overdoped cuprates. The average frequency of an EBSDF provides the timescale for the spin fluctuations to form Cooper pairs. This timescale is directly associated with retarded interactions between electrons. Using this timescale and Fermi velocity, a reasonable superconducting coherence length, which reflects the size of the Cooper pair, can be extracted. The obtained coherence lengths were consistent with those measured via other experimental techniques. Therefore, the formation of Cooper pairs in cuprates can be explained by spin fluctuations, the timescales of which appear in EBSDFs. Consequently, EBSDFs provide crucial information on the timescale of the microscopic mechanism of Cooper pair formation.

RENORMALIZATION OF FERMI VELOCITY IN A COMPOSITE TWO DIMENSIONAL ELECTRON GAS

1993 ◽  
Vol 07 (01n03) ◽  
pp. 87-94 ◽  
Author(s):  
M. WEGER ◽  
L. BURLACHKOV
Keyword(s):  
Electron Gas ◽  
Fermi Velocity ◽  
Bohr Radius ◽  
Dimensional Electron ◽  
Temperature Dependent ◽  
Two Dimensional Electron Gas ◽  
Self Energy ◽  
2D System ◽  
Dimensional Electron Gas ◽  
The One

We calculate the self-energy Σ(k, ω) of an electron gas with a Coulomb interaction in a composite 2D system, consisting of metallic layers of thickness d ≳ a 0, where a 0 = ħ2∊1/ me 2 is the Bohr radius, separated by layers with a dielectric constant ∊2 and a lattice constant c perpendicular to the planes. The behavior of the electron gas is determined by the dimensionless parameters k F a 0 and k F c ∊2/∊1. We find that when ∊2/∊1 is large (≈5 or more), the velocity v(k) becomes strongly k-dependent near k F , and v ( k F ) is enhanced by a factor of 5-10. This behavior is similar to the one found by Lindhard in 1954 for an unscreened electron gas; however here we take screening into account. The peak in v(k) is very sharp (δ k/k F is a few percent) and becomes sharper as ∊2/∊1 increases. This velocity renormalization has dramatic effects on the transport properties; the conductivity at low T increases like the square of the velocity renormalization and the resistivity due to elastic scattering becomes temperature dependent, increasing approximately linearly with T. For scattering by phonons, ρ ∝ T 2. Preliminary measurements suggest an increase in v k in YBCO very close to k F .

Determination of the Fermi Velocity by the High-Field Tilt Effect

1960 ◽  
Vol 120 (4) ◽  
pp. 1261-1265 ◽  
Author(s):  
Harold N. Spector
Keyword(s):  
High Field ◽  
Fermi Velocity

Novel features of electromagnetic waves in an isotropic degenerate electron-ion plasma

2021 ◽  
Author(s):  
P. Maryam ◽  
Rozina Chaudhary ◽  
Shahid Ali ◽  
Hassan Amir Shah ◽  
Stefaan Poedts
Keyword(s):  
Nonlinear Interaction ◽  
Electromagnetic Waves ◽  
Tunneling Effect ◽  
Fermi Velocity ◽  
Degenerate Electron ◽  
Linear Dispersion ◽  
Direct Function ◽  
Ion Plasma ◽  
Damping Rate ◽  
Electron Quantum

Abstract Within the framework of kinetic theory, the nonlinear interaction of electromagnetic waves (EMWs) with a degenerate electron-ion plasma is studied to account for the electron quantum mechanical effects. For this purpose, a specific quantum regime is considered, for which the degenerate electron Fermi velocity is assumed to be taken of the order of group velocity of EMWs. This eventually leads to the existence of nonlinear Landau damping rate for the EMWs in the presence of electron Ponderomotive force. The electrons-ion density oscillations may be arisen from the nonlinear interaction of EMWs, leading to a new type of nonlinear Schrödinger equation in terms of a complex amplitude for electromagnetic pump wave. The profiles of nonlinear damping rate reveal that EMWs become less damped for increasing the quantum tunnelling effects. The electrostatic response for the linear electrostatic waves is also investigated and derived a linear dispersion for the ion-acoustic damping rate. The latter is a direct function of electron Fermi speed and does not rely on the Bohm tunneling effect. The obtained results are numerically analyzed for the two microwaves of different harmonics in the context of nonrelativistic astrophysical dense plasma environments, e.g., white dwarfs, where the electron quantum corrections cannot be ignored.

Sharp gap edge and determination of the fermi velocity in Y1Ba2Cu3O7?? by point contact spectroscopy

1992 ◽  
Vol 5 (2) ◽  
pp. 191-194 ◽  
Author(s):  
Nir Mass ◽  
D. Ilzycer ◽  
G. Deutscher ◽  
G. Desgardin ◽  
I. Monot ◽  
...  
Keyword(s):  
Point Contact ◽  
Fermi Velocity ◽  
Point Contact Spectroscopy
Sign in / Sign up

Export Citation Format

Share Document