Electron-phonon interaction, ultrasonic attenuation, and Eliashberg functionα2F(ω) in impure metals

1987 ◽  
Vol 36 (5) ◽  
pp. 2513-2518 ◽  
Author(s):  
D. Belitz
2012 ◽  
Vol 482-484 ◽  
pp. 819-823
Author(s):  
Hui Kong ◽  
Wei Dai ◽  
Shuai Shao

The longitudinal ultrasonic velocity (V) and attenuation at a frequency of 10MHz have been measured in single-phase polycrystalline La1/3Sr2/3Fe0.95Co0.05O3 from 20K to 300K. The temperature dependence of resistivity indicates that La1/3Sr2/3Fe0.95Co0.05O3 undergoes charge ordering transition at TCO. A dramatic increase in V is observed at TCO, which is accompanied by a sharp peak in attenuation. This simultaneous occurrence of resistivity and ultrasonic anomalous features implies extremely strong electron-phonon interaction, which is due to the the Jahn-Teller effect of high-spin Fe4+. Below TCO, another softening in V accompanied by a wide ultrasonic attenuation peak is observed. The analysis of the results suggests that these anomalies may correspond to the breathing-type distortion of Fe-O octahedron.


1960 ◽  
Vol 13 (2) ◽  
pp. 446 ◽  
Author(s):  
JC Fisher

A comparison is made between (a) the trial ground state composed of a linear combination of normal state configurations in which individual electron states of opposite momentum and equal spin projection (k t, -k t) and (k t, -k t), abbreviated (kcr, -kcr), are both either occupied or unoccupied, and (b) the trial ground state with (k t , -k t ) pairing proposed by Bardeen, Cooper, and Schrieffer. The two trial states lead to identical thermodynamics as long as an average matrix element -V = < Vkle' >av is treated as a disposable parameter. They lead to similar coherence effects for ultrasonic attenuation and nuclear spin relaxation. They differ in that spin paramagnetism is predicted for (kcr, -kcr) pairing. Detailed knowledge of the electron-phonon interaction in superconductors seems at present inadequate to rule out either possibility for all superconductors.


2018 ◽  
Vol 30 (12) ◽  
pp. 3-16
Author(s):  
A. Berezin ◽  
◽  
Yu. Volkov ◽  
M. Markov ◽  
I. Tarakanov ◽  
...  

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