scholarly journals The determination of the electron–phonon interaction from tunneling data in the two-band superconductor MgB2

2004 ◽  
Vol 408-410 ◽  
pp. 353-354 ◽  
Author(s):  
D. Daghero ◽  
R.S. Gonnelli ◽  
G.A. Ummarino ◽  
O.V. Dolgov ◽  
J. Kortus ◽  
...  
2020 ◽  
Vol 15 (1) ◽  
Author(s):  
Mingming Yang ◽  
Longlong Wang ◽  
Xiaofen Qiao ◽  
Yi Liu ◽  
Yufan Liu ◽  
...  

Abstract The defects into the hexagonal network of a sp2-hybridized carbon atom have been demonstrated to have a significant influence on intrinsic properties of graphene systems. In this paper, we presented a study of temperature-dependent Raman spectra of G peak and D’ band at low temperatures from 78 to 318 K in defective monolayer to few-layer graphene induced by ion C+ bombardment under the determination of vacancy uniformity. Defects lead to the increase of the negative temperature coefficient of G peak, with a value almost identical to that of D’ band. However, the variation of frequency and linewidth of G peak with layer number is contrary to D’ band. It derives from the related electron-phonon interaction in G and D’ phonon in the disorder-induced Raman scattering process. Our results are helpful to understand the mechanism of temperature-dependent phonons in graphene-based materials and provide valuable information on thermal properties of defects for the application of graphene-based devices.


1982 ◽  
Vol 60 (10) ◽  
pp. 1490-1495 ◽  
Author(s):  
A. Manoogian

An empirical method was used to separate the temperature shift curves of the A- and B-exciton energies in CdS. It was found that the lattice dilation contributed an amount −2.3 × 10−5 eV/K to the temperature shift, and the frequencies of the terms representing the electron–phonon interaction were found to correspond to the average frequencies of the phonons in CdS. The data on the semiconductors analyzed up to now by the empirical method (C, Si, Ge, CdS) were examined at the melting point temperatures of the materials and it was found that the combined results could be described by simple equations. It was found that the r.m.s. vibrational amplitude of the atoms in the above four materials was nearly identical at their melting temperatures.


1982 ◽  
Vol 90 (9) ◽  
pp. 471-473 ◽  
Author(s):  
D.M. Burnell ◽  
E.L. Wolf

2001 ◽  
Vol 63 (7) ◽  
Author(s):  
G. V. Kamarchuk ◽  
A. V. Khotkevich ◽  
V. M. Bagatsky ◽  
V. G. Ivanov ◽  
P. Molinié ◽  
...  

1993 ◽  
Vol 07 (27) ◽  
pp. 1733-1739 ◽  
Author(s):  
VALERY IVANOV ◽  
RENATO PUCCI ◽  
VLADIMIR YARUNIN

We propose a model for A x C 60 systems involving both Hubbard repulsion of alkali electrons in the narrow LUMO band of C 60 and their interaction with both high- and low-frequency phonon modes. In our approach, these phonons play different roles in the determination of a nonzero interband hopping integral hp, which increases the value of the superconductive critical temperature T c . A nonadiabatical approximation is used for the calculation of the soft-phonon-electron scattering. In the framework of the Gor’kov method and the kinematical high-T c mechanism, we have obtained an expression for T c as a function of the A atom concentration x and found that the superconducting gap Δ0 satisfies the inequality 2Δ0/T c >3.53. The qualitative agreements with experimental data were obtained.


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