scholarly journals Time-dependent equation for the magnetic order parameter near the quantum critical point in multiband superconductors with a spin-density wave

2013 ◽  
Vol 88 (22) ◽  
Author(s):  
Andreas Moor ◽  
Anatoly F. Volkov ◽  
Konstantin B. Efetov
2019 ◽  
Vol 123 (24) ◽  
Author(s):  
P. G. Niklowitz ◽  
M. Hirschberger ◽  
M. Lucas ◽  
P. Cermak ◽  
A. Schneidewind ◽  
...  

2013 ◽  
Vol 28 (01) ◽  
pp. 1450005 ◽  
Author(s):  
M. J. LUO

In this paper, we propose a holographic theory to explain a number of anomalous critical phenomena observed in certain heavy fermion metals, e.g. CeCu 5.9 Au 0.1 and YbRh 2( Si 0.95 Ge 0.05)2, which are incompatible with any conventional spin-density-wave quantum critical point theory. We show that the non-Gaussian nature of the fixed point from holography plays an essential role in the physics of these materials near a quantum critical point, which is not in the same universality class of the spin-density-wave type fixed point. The critical spin fluctuations at the non-Gaussian fixed point are strongly anisotropic, localized in spatial directions and critical in temporal direction with critical exponent 2/3 in frequency over temperature dependence at low temperature. The local critical exponent tends to unity which leads to a constant spin relaxation rate in the quantum critical regime at high temperature. The stability of the fixed point is also discussed.


2002 ◽  
Vol 16 (20n22) ◽  
pp. 2991-2991
Author(s):  
P. COLEMAN

This talk will discuss non-Fermi liquid and quantum critical behavior in heavy fermion materials, focussing on the mechanism by which the electron mass appears to diverge at the quantum critical point. Is the quantum critical point merely a case of electron diffraction off a quantum critical spin density wave, or does it involve a fundamental break-down in the composite nature of the heavy electron place at the quantum critical point? We discuss the nature of the critical langrangian and show that the Hall constant changes continuously in the first scenario, but may "jump" discontinuously at a quantum critical point where the composite character of the electron quasiparticles changes.


2017 ◽  
Vol 114 (21) ◽  
pp. 5384-5388 ◽  
Author(s):  
P. F. S. Rosa ◽  
J. Kang ◽  
Yongkang Luo ◽  
N. Wakeham ◽  
E. D. Bauer ◽  
...  

Applied pressure drives the heavy-fermion antiferromagnet CeRhIn5 toward a quantum critical point that becomes hidden by a dome of unconventional superconductivity. Magnetic fields suppress this superconducting dome, unveiling the quantum phase transition of local character. Here, we show that 5% magnetic substitution at the Ce site in CeRhIn5, either by Nd or Gd, induces a zero-field magnetic instability inside the superconducting state. This magnetic state not only should have a different ordering vector than the high-field local-moment magnetic state, but it also competes with the latter, suggesting that a spin-density-wave phase is stabilized in zero field by Nd and Gd impurities, similarly to the case of Ce0.95Nd0.05CoIn5. Supported by model calculations, we attribute this spin-density wave instability to a magnetic-impurity-driven condensation of the spin excitons that form inside the unconventional superconducting state.


1993 ◽  
Vol 03 (C2) ◽  
pp. C2-225-C2-230
Author(s):  
S. E. BROWN ◽  
B. ALAVI ◽  
W. G. CLARK ◽  
M. E. HANSON ◽  
B. KLEMME

1996 ◽  
Vol 53 (12) ◽  
pp. 7699-7703 ◽  
Author(s):  
J. C. Lasjaunias ◽  
K. Biljaković ◽  
P. Monceau

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