Superconductivity in Single Crystal Tl

1974 ◽  
Vol 52 (16) ◽  
pp. 1504-1509 ◽  
Author(s):  
P. T. Truant ◽  
J. P. Carbotte
Keyword(s):  
Single Crystal ◽  
Phonon Dispersion ◽  
Scattering Data ◽  
Electron Mass ◽  
Phonon Dispersion Curves ◽  
Electron Phonon Interaction ◽  
Gap Anisotropy ◽  
Crystal Transition ◽  
The Mean ◽  
Pure Single Crystal

We have used a model of the electron–phonon interaction in Tl which is consistent with neutron scattering data on the phonon dispersion curves as well as the superconducting tunneling data on the isotropic electron–phonon function α2(ω)F(ω) to explore the amount of anisotropy that can be expected in select properties of Tl. First the Fermi surface (FS) variation of the electron mass renormalization parameter λ(k) is determined. Then the superconducting gap Δ(k) is obtained for many k's on the FS. The mean square gap anisotropy is calculated. The pure single crystal transition temperature is obtained and compared with the dirty limit.

Phonon renormalization of the electronic effective mass

1969 ◽  
Vol 47 (10) ◽  
pp. 1107-1116 ◽  
Author(s):  
J. P. Carbotte ◽  
R. C. Dynes ◽  
P. N. Trofimenkoff
Keyword(s):  
Effective Mass ◽  
Phonon Dispersion ◽  
Inelastic Neutron Scattering ◽  
Inelastic Neutron ◽  
Force Constants ◽  
Coupling Constant ◽  
Phonon Dispersion Curves ◽  
Electron Phonon Interaction ◽  
Phonon Renormalization ◽  
Pseudo Potential

We have made detailed first principle calculations of the phonon contribution to the renormalization of the electronic effective mass of a number of simple metals and alloys. The phonon frequencies and polarization vectors are generated from the interatomic force constants for the material. The force constants are taken from a Born – von Kármán analysis of the experimental phonon dispersion curves determined by inelastic neutron scattering. The electron–phonon interaction is treated using pseudo-potential theory which relates the coupling constant to the electron–ion form factor. For a spherical Fermi surface it is then possible to evaluate numerically the expression for the effective mass with no further approximations. We compare the results obtained with previous work when available and with experiment otherwise.

Critical temperature with paramagnetic and normal impurities under the square well model

1984 ◽  
Vol 62 (2) ◽  
pp. 158-166 ◽  
Author(s):  
J. W. Blezius ◽  
J. P. Carbotte
Keyword(s):  
Energy Gap ◽  
Mean Square ◽  
Electron Phonon Interaction ◽  
The Past ◽  
Paramagnetic Impurities ◽  
Well Model ◽  
Gap Anisotropy ◽  
The Mean ◽  
Square Well ◽  
Pairing Potential

In the past, it has been shown that in superconductors where paramagnetic impurities are not involved, the results obtained from an analysis in the Eliashberg model with a square well approximation to the electron–phonon interaction are related simply to the analogous results of the Bardeen–Cooper–Schrieffer (BCS) model. The relation consists of a substitution of the mean square energy gap anisotropy for the mean square pairing potential anisotropy and of adding a (1 + λ) mass renormalization factor. The present paper considers a paramagnetic case in the same model and it is found that the relation to the BCS result is different from that of previously studied cases.

Surface lattice dynamics and electron–phonon interaction in cesium ultra-thin films

2017 ◽  
Vol 19 (25) ◽  
pp. 16358-16364 ◽  
Author(s):  
D. Campi ◽  
M. Bernasconi ◽  
G. Benedek ◽  
A. P. Graham ◽  
J. P. Toennies
Keyword(s):  
Ultrathin Films ◽  
Density Functional ◽  
Phonon Dispersion ◽  
Phonon Interaction ◽  
Phonon Dispersion Curves ◽  
Helium Atom Scattering ◽  
Electron Phonon Interaction ◽  
Atom Scattering ◽  
Density Functional Perturbation Theory ◽  
Mass Enhancement

The phonon dispersion curves of ultrathin films of Cs(110) on Pt(111) measured with inelastic helium atom scattering (HAS) are reported and compared with density-functional perturbation theory calculations. The mass-enhancement factor is derived from the temperature dependence of the HAS Debye–Waller exponent.

Phonon Dispersion and Kohn Anomaues in the Alloy Cu0.84Al0.16

1989 ◽  
Vol 166 ◽  
Author(s):  
Henry Chou ◽  
S. M. Shapiro ◽  
S. C. Moss ◽  
Mark Mostoller
Keyword(s):  
Phonon Dispersion ◽  
Electron Interaction ◽  
Present System ◽  
High Symmetry ◽  
Phonon Dispersion Curves ◽  
Electron Phonon Interaction ◽  
Atomic Force ◽  
Complete Set ◽  
Pure Cu ◽  
Better Than

ABSTRACTWe have made detailed measurements of phonon frequencies along all high-symmetry directions on a large single crystal of Cu0.84Al0.16 at room temperature. Phonon frequencies were ascertained to better than ±0.03 meV. Inter-atomic force constants and vibrational density of states were calculated by performing a Born-von Karman analysis on the complete set of phonon dispersion curves. In contrast to the case of pure Cu, no evident Kohn anomaly (neither in the phonon dispersion itself nor in the derivatives) was observed near the expected wave vector q=2kF. The absence of Kohn anomalies in the present system could be due either to a smeared out Fermi surface or to the possibility that the electron-electron interaction which screens the inter-ionic potential is not the dominant interaction in the system; i.e. the existence of Kohn anomalies in these alloys may depend mainly on the details of the electron-phonon interaction.

Phonon Properties of Americium Sulphide

2016 ◽  
Vol 28 ◽  
pp. 125-128
Author(s):  
Balwant Singh Arya ◽  
Mahendra Aynyas ◽  
Sankar P. Sanyal
Keyword(s):  
Present Model ◽  
Phonon Dispersion ◽  
Dispersion Curves ◽  
Phonon Interaction ◽  
Phonon Dispersion Curves ◽  
Electron Phonon Interaction ◽  
Breathing Motion ◽  
Shell Models ◽  
Phonon Properties

We have reported the phonon properties of AmS by using breathing shell models (BSM) which includes breathing motion of electrons of the Am atoms due to f-d hybridization. The phonon dispersion curves, density of states and specific heat calculated from present model. The calculated phonon dispersion curves of AmS are presented follow the same trend as observed in uranium sulphide. We have discussed the significance of this approach in predicting the phonon dispersion curves of this compound and examine the role of electron-phonon interaction.

Phonon dispersion curves in an argon single crystal at high pressure by inelastic x-ray scattering

2001 ◽  
Vol 63 (22) ◽  
Author(s):  
F. Occelli ◽  
M. Krisch ◽  
P. Loubeyre ◽  
F. Sette ◽  
R. Le Toullec ◽  
...  
Keyword(s):  
High Pressure ◽  
Single Crystal ◽  
Phonon Dispersion ◽  
Dispersion Curves ◽  
Phonon Dispersion Curves ◽  
X Ray ◽  
X Ray Scattering ◽  
Ray Scattering

scholarly journals Study of the Electron-Phonon Interaction in Metal Diborides MeB2 (Me = Zr, Nb, Ta, Mg) by Point-Contact Spectroscopy

2003 ◽  
Vol 17 (10n12) ◽  
pp. 657-666 ◽  
Author(s):  
I. K. Yanson ◽  
Yu. G. Naidyuk ◽  
O. E. Kvitnitskaya ◽  
V. V. Fisun ◽  
N. L. Bobrov ◽  
...  
Keyword(s):  
Phonon Dispersion ◽  
Point Contact ◽  
Band Model ◽  
Phonon Interaction ◽  
Metal Compounds ◽  
Phonon Dispersion Curves ◽  
Electron Phonon Interaction ◽  
Excess Current ◽  
Metal Diborides ◽  
Two Band Model

We review investigations of the electron-phonon interaction (EPI) in metal diborides MeB2 (Me = Zr, Nb, Ta, Mg) by point-contact (PC) spectroscopy. For transition metal compounds the PC EPI functions were recovered and EPI parameter λ ≲ 0.1 were estimated. The data are consistent with the measured surface phonon dispersion curves. The low λ value questions some reports about superconductivity in these compounds. Contrary, EPI in superconducting MgB2 films manifests also in the PC spectra itself by virtue of an elastic EPI contribution to the excess current determined by the energy dependence of the superconducting order parameter. To analyse the phonon features in the PC spectra of MgB2 a two-band model is exploited and the proximity effect in the k-space is suggested.

Pressure Dependence of the Energy Gap Anisotropy in Aluminum

1972 ◽  
Vol 50 (21) ◽  
pp. 2568-2573
Author(s):  
C. R. Leavens ◽  
J. P. Carbotte
Keyword(s):  
Fermi Surface ◽  
Single Crystal ◽  
Pressure Dependence ◽  
Energy Gap ◽  
Superconducting Energy Gap ◽  
Gap Anisotropy ◽  
Pure Single Crystal

We have calculated the superconducting energy gap for a large number of points on the irreducible (1/48)th of the Fermi surface of pure single-crystal aluminum both at zero and finite pressure. It is found that the energy gap anisotropy in aluminum increases with increasing pressure.

Sign in / Sign up

Export Citation Format

Share Document