scholarly journals Special role of the first Matsubara frequency for superconductivity near a quantum critical point: Nonlinear gap equation below Tc and spectral properties in real frequencies

2019 ◽  
Vol 99 (14) ◽  
Author(s):  
Yi-Ming Wu ◽  
Artem Abanov ◽  
Yuxuan Wang ◽  
Andrey V. Chubukov
Keyword(s):  
Critical Point ◽  
Spectral Properties ◽  
Quantum Critical Point ◽  
Special Role ◽  
Gap Equation ◽  
Matsubara Frequency ◽  
Quantum Critical

scholarly journals Superconductivity near a Quantum-Critical Point: The Special Role of the First Matsubara Frequency

2016 ◽  
Vol 117 (15) ◽  
Author(s):  
Yuxuan Wang ◽  
Artem Abanov ◽  
Boris L. Altshuler ◽  
Emil A. Yuzbashyan ◽  
Andrey V. Chubukov
Keyword(s):  
Critical Point ◽  
Quantum Critical Point ◽  
Special Role ◽  
Matsubara Frequency ◽  
Quantum Critical

scholarly journals Role of disorder on the quantum critical point of a model for heavy fermions

2001 ◽  
Vol 64 (14) ◽  
Author(s):  
T. G. Rappoport ◽  
A. Saguia ◽  
B. Boechat ◽  
M. A. Continentino
Keyword(s):  
Critical Point ◽  
Heavy Fermions ◽  
Quantum Critical Point ◽  
Quantum Critical

scholarly journals Nematic quantum critical point without magnetism in FeSe1−xSx superconductors

2016 ◽  
Vol 113 (29) ◽  
pp. 8139-8143 ◽  
Author(s):  
Suguru Hosoi ◽  
Kohei Matsuura ◽  
Kousuke Ishida ◽  
Hao Wang ◽  
Yuta Mizukami ◽  
...  
Keyword(s):  
Critical Point ◽  
High Temperature Superconductors ◽  
Quantum Critical Point ◽  
Antiferromagnetic Order ◽  
Iron Pnictide ◽  
Nematic Order ◽  
Unconventional Superconductors ◽  
Quantum Critical ◽  
The Impact

In most unconventional superconductors, the importance of antiferromagnetic fluctuations is widely acknowledged. In addition, cuprate and iron-pnictide high-temperature superconductors often exhibit unidirectional (nematic) electronic correlations, including stripe and orbital orders, whose fluctuations may also play a key role for electron pairing. In these materials, however, such nematic correlations are intertwined with antiferromagnetic or charge orders, preventing the identification of the essential role of nematic fluctuations. This calls for new materials having only nematicity without competing or coexisting orders. Here we report systematic elastoresistance measurements in FeSe1−xSx superconductors, which, unlike other iron-based families, exhibit an electronic nematic order without accompanying antiferromagnetic order. We find that the nematic transition temperature decreases with sulfur content x; whereas, the nematic fluctuations are strongly enhanced. Near x≈0.17, the nematic susceptibility diverges toward absolute zero, revealing a nematic quantum critical point. The obtained phase diagram for the nematic and superconducting states highlights FeSe1−xSx as a unique nonmagnetic system suitable for studying the impact of nematicity on superconductivity.

scholarly journals Superconductivity at an antiferromagnetic quantum critical point: Role of energy fluctuations

2018 ◽  
Vol 98 (21) ◽  
Author(s):  
Jian Kang ◽  
Rafael M. Fernandes ◽  
Elihu Abrahams ◽  
Peter Wölfle
Keyword(s):  
Critical Point ◽  
Quantum Critical Point ◽  
Quantum Critical

scholarly journals Tuning the charge density wave quantum critical point and the appearance of superconductivity in TiSe2

2021 ◽  
Vol 3 (3) ◽  
Author(s):  
Sangyun Lee ◽  
Tae Beom Park ◽  
Jihyun Kim ◽  
Soon-Gil Jung ◽  
Won Kyung Seong ◽  
...  
Keyword(s):  
Charge Density ◽  
Critical Point ◽  
Charge Density Wave ◽  
Density Wave ◽  
Quantum Critical Point ◽  
Quantum Critical

scholarly journals Lattice-shifted nematic quantum critical point in FeSe1−xSx

2021 ◽  
Vol 6 (1) ◽  
Author(s):  
S. Chibani ◽  
D. Farina ◽  
P. Massat ◽  
M. Cazayous ◽  
A. Sacuto ◽  
...  
Keyword(s):  
Transition Temperature ◽  
Critical Point ◽  
Degrees Of Freedom ◽  
Quantum Critical Point ◽  
Substantial Effect ◽  
Low Energy ◽  
Elastic Coupling ◽  
Superconducting Transition ◽  
Local Moments ◽  
Quantum Critical

AbstractWe report the evolution of nematic fluctuations in FeSe1−xSx single crystals as a function of Sulfur content x across the nematic quantum critical point (QCP) xc ~ 0.17 via Raman scattering. The Raman spectra in the B1g nematic channel consist of two components, but only the low energy one displays clear fingerprints of critical behavior and is attributed to itinerant carriers. Curie–Weiss analysis of the associated nematic susceptibility indicates a substantial effect of nemato-elastic coupling, which shifts the location of the nematic QCP. We argue that this lattice-induced shift likely explains the absence of any enhancement of the superconducting transition temperature at the QCP. The presence of two components in the nematic fluctuations spectrum is attributed to the dual aspect of electronic degrees of freedom in Hund’s metals, with both itinerant carriers and local moments contributing to the nematic susceptibility.

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