scholarly journals Crossover from coherent quasiparticles to incoherent hole carriers in underdoped cuprates

2009 ◽  
Vol 79 (14) ◽  
Author(s):  
M. Hashimoto ◽  
T. Yoshida ◽  
K. Tanaka ◽  
A. Fujimori ◽  
M. Okusawa ◽  
...  
Keyword(s):  
Underdoped Cuprates

scholarly journals What is strange about high-temperature superconductivity in cuprates?

2017 ◽  
Vol 31 (25) ◽  
pp. 1745005
Author(s):  
I. Božović ◽  
X. He ◽  
J. Wu ◽  
A. T. Bollinger
Keyword(s):  
Phase Diagram ◽  
Cuprate Superconductors ◽  
High Temperature Superconductivity ◽  
Einstein Condensation ◽  
Strongly Correlated ◽  
Bose Einstein Condensation ◽  
Ultimate Question ◽  
Underdoped Cuprates ◽  
Bose Einstein ◽  
Superconducting Parameters

Cuprate superconductors exhibit many features, but the ultimate question is why the critical temperature ([Formula: see text]) is so high. The fundamental dichotomy is between the weak-pairing, Bardeen–Cooper–Schrieffer (BCS) scenario, and Bose–Einstein condensation (BEC) of strongly-bound pairs. While for underdoped cuprates it is hotly debated which of these pictures is appropriate, it is commonly believed that on the overdoped side strongly-correlated fermion physics evolves smoothly into the conventional BCS behavior. Here, we test this dogma by studying the dependence of key superconducting parameters on doping, temperature, and external fields, in thousands of cuprate samples. The findings do not conform to BCS predictions anywhere in the phase diagram.

scholarly journals Extent of Fermi-surface reconstruction in the high-temperature superconductor HgBa2CuO4+δ

2020 ◽  
Vol 117 (18) ◽  
pp. 9782-9786
Author(s):  
Mun K. Chan ◽  
Ross D. McDonald ◽  
B. J. Ramshaw ◽  
Jon B. Betts ◽  
Arkady Shekhter ◽  
...  
Keyword(s):  
Fermi Surface ◽  
Surface Reconstruction ◽  
Field Measurements ◽  
Temperature Dependent ◽  
Crucial Issue ◽  
Critical Fields ◽  
Sign Change ◽  
Underdoped Cuprates ◽  
Upper Critical Fields ◽  
Fermi Surface Reconstruction

High magnetic fields have revealed a surprisingly small Fermi surface in underdoped cuprates, possibly resulting from Fermi-surface reconstruction due to an order parameter that breaks translational symmetry of the crystal lattice. A crucial issue concerns the doping extent of such a state and its relationship to the principal pseudogap and superconducting phases. We employ pulsed magnetic-field measurements on the cuprate HgBa2CuO4+δ to identify signatures of Fermi-surface reconstruction from a sign change of the Hall effect and a peak in the temperature-dependent planar resistivity. We trace the termination of Fermi-surface reconstruction to two hole concentrations where the superconducting upper critical fields are found to be enhanced. One of these points is associated with the pseudogap endpoint near optimal doping. These results connect the Fermi-surface reconstruction to both superconductivity and the pseudogap phenomena.

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