THERMAL CONDUCTIVITY OF HIGH-TEMPERATURE SUPERCONDUCTORS

Author(s):  
Ctirad Uher
1991 ◽  
Vol 05 (12) ◽  
pp. 2003-2035 ◽  
Author(s):  
MANUEL D. NUÑEZ REGUEIRO ◽  
DARÍO CASTELLO

We review and analyze the data on the thermal conductivity of both ceramic and single crystal samples of high temperature superconductors. A universal pattern can be extracted and interpreted in the following way: phonons are the main heat carriers in these materials, and in the high temperature range the thermal conductivity κ is almost constant due to phonon scattering against disorder; below the superconducting transition temperature κ increases as phonon scattering against carriers condensing into the superconducting state decreases and at still lower temperatures there is a region in which a T2 law is obeyed that most probably is due to resonant phonon scattering against low energy excitations, i.e. tunneling systems similar to those found in disordered materials. The origin of the relevant disorder is discussed.


2011 ◽  
Vol 25 (09) ◽  
pp. 663-678 ◽  
Author(s):  
VINOD ASHOKAN ◽  
B. D. INDU

An ab initio formulation of relaxation times of various contributing processes have been observed with newer understanding in terms of electron and phonon line widths. This is dealt with the help of double time temperature-dependent Green's function via a non-perturbative approach using a crystal Hamiltonian which comprises of the effects of electrons, phonons, impurities, anharmonicities and interactions thereof. The frequency line widths is observed as an extremely sensitive quantity in the transport phenomena of high temperature superconductors (HTS) as a collection of a large number of scattering processes, namely: boundary scattering, impurity scattering, multi-phonon scattering, interference scattering, electron–phonon processes and resonance scattering. The behavior of electrons and phonons is then investigated to describe the thermal conductivity of a variety of HTS samples specially in the vicinity of transition temperature to successfully explain the spectacular dip region of thermal conductivity curve which was lacking in explanation earlier with a sound physical justification.


1988 ◽  
Vol 67 (4) ◽  
pp. 401-404 ◽  
Author(s):  
M. Núñez Regueiro ◽  
M.A. Izbizky ◽  
P. Esquinazi

1994 ◽  
Vol 91 (7) ◽  
pp. 571-575 ◽  
Author(s):  
H. Bougrine ◽  
S. Sergeenkov ◽  
M. Ausloos ◽  
R. Cloots ◽  
V.V. Gridin

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