Theory on Pseudogap State and Superconducting State in Strong Coupling Superconductors

2000 ◽  
Vol 69 (7) ◽  
pp. 2240-2249 ◽  
Author(s):  
Takanobu Jujo ◽  
Youichi Yanase ◽  
Kosaku Yamada
Keyword(s):  
Strong Coupling ◽  
Superconducting State ◽  
Pseudogap State

scholarly journals Characterization of the superconducting phase in tellurium hydride at high pressure

2019 ◽  
Vol 33 (16) ◽  
pp. 1950169 ◽  
Author(s):  
Tomasz P. Zemła ◽  
Klaudia M. Szczȩśniak ◽  
Adam Z. Kaczmarek ◽  
Svitlana V. Turchuk
Keyword(s):  
High Pressure ◽  
Critical Temperature ◽  
Strong Coupling ◽  
Superconducting State ◽  
Density Functional ◽  
Superconducting Phase ◽  
Bcs Theory ◽  
Electron Mass ◽  
Eliashberg Equations ◽  
Effective Electron

At present, hydrogen-based compounds constitute one of the most promising classes of materials for applications as phonon-mediated high-temperature superconductors. Herein, the behavior of the superconducting phase in tellurium hydride (HTe) at high pressure (p = 300 GPa) is analyzed in detail, by using the isotropic Migdal–Eliashberg equations. The chosen pressure conditions are considered here as a case study which corresponds to the highest critical temperature value [Formula: see text] in the analyzed material, as determined within recent density functional theory simulations. It is found that the Migdal–Eliashberg formalism, which constitutes a strong-coupling generalization of the Bardeen–Cooper–Schrieffer (BCS) theory, predicts that the critical temperature value ([Formula: see text] K) is higher than previous estimates of the McMillan formula. Further investigations show that the characteristic dimensionless ratios for the thermodynamic critical field, the specific heat for the superconducting state, and the superconducting band gap exceed the limits of the BCS theory. In this context, also the effective electron mass is not equal to the bare electron mass as provided by the BCS theory. On the basis of these findings it is predicted that the strong-coupling and retardation effects play pivotal role in the superconducting phase of HTe at 300 GPa, in agreement with similar theoretical estimates for the sibling hydrogen and hydrogen-based compounds. Hence, it is suggested that the superconducting state in HTe cannot be properly described within the mean-field picture of the BCS theory.

Superconducting state in strong coupling

1984 ◽  
Vol 51 (5) ◽  
pp. 339-342 ◽  
Author(s):  
V.Z. Kresin ◽  
H. Gutfreund ◽  
W.A. Little
Keyword(s):  
Strong Coupling ◽  
Superconducting State

scholarly journals Investigations of proximity-induced superconductivity in the topological insulator Bi2Te3 by microRaman spectroscopy

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
D. Kiphart ◽  
Y. Harkavyi ◽  
K. Balin ◽  
J. Szade ◽  
B. Mróz ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Charge Transport ◽  
Topological Insulator ◽  
Superconducting State ◽  
High Temperature Superconductor ◽  
Superconducting Gap ◽  
Pseudogap State ◽  
Hybrid Device ◽  
Higher Temperature ◽  
Microraman Spectroscopy

AbstractWe used the topological insulator (TI) Bi2Te3 and a high-temperature superconductor (HTSC) hybrid device for investigations of proximity-induced superconductivity (PS) in the TI. Application of the superconductor YBa2Cu3O7-δ (YBCO) enabled us to access higher temperature and energy scales for this phenomenon. The HTSC in the hybrid device exhibits emergence of a pseudogap state for T > Tc that converts into a superconducting state with a reduced gap for T < Tc. The conversion process has been reflected in Raman spectra collected from the TI. Complementary charge transport experiments revealed emergence of the proximity-induced superconducting gap in the TI and the reduced superconducting gap in the HTSC, but no signature of the pseudogap. This allowed us to conclude that Raman spectroscopy reveals formation of the pseudogap state but cannot distinguish the proximity-induced superconducting state in the TI from the superconducting state in the HTSC characterised by the reduced gap. Results of our experiments have shown that Raman spectroscopy is a complementary technique to classic charge transport experiments and is a powerful tool for investigation of the proximity-induced superconductivity in the Bi2Te3.

scholarly journals Influence of strong-coupling and retardation effects on superconducting state in YB6 compound

2018 ◽  
Vol 546 ◽  
pp. 44-48
Author(s):  
A.M. Bujak ◽  
K.A. Szewczyk ◽  
M. Kostrzewa ◽  
K.M. Szczȩśniak ◽  
M.A. Sowińska
Keyword(s):  
Strong Coupling ◽  
Superconducting State ◽  
Retardation Effects

Specific Heat Measurements ofBa0.68K0.32Fe2As2Single Crystals: Evidence for a Multiband Strong-Coupling Superconducting State

2010 ◽  
Vol 105 (2) ◽  
Author(s):  
P. Popovich ◽  
A. V. Boris ◽  
O. V. Dolgov ◽  
A. A. Golubov ◽  
D. L. Sun ◽  
...  
Keyword(s):  
Specific Heat ◽  
Strong Coupling ◽  
Superconducting State

scholarly journals Three energy scales characterizing the competing pseudogap state, the incoherent, and the coherent superconducting state in high-Tccuprates

2011 ◽  
Vol 83 (10) ◽  
Author(s):  
Y. Okada ◽  
T. Kawaguchi ◽  
M. Ohkawa ◽  
K. Ishizaka ◽  
T. Takeuchi ◽  
...  
Keyword(s):  
Superconducting State ◽  
Pseudogap State
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