scholarly journals Quantum critical behavior in itinerant electron systems: Eliashberg theory and instability of a ferromagnetic quantum critical point

2006 ◽  
Vol 74 (19) ◽  
Author(s):  
Jérôme Rech ◽  
Catherine Pépin ◽  
Andrey V. Chubukov
Keyword(s):  
Critical Point ◽  
Critical Behavior ◽  
Quantum Critical Point ◽  
Itinerant Electron ◽  
Electron Systems ◽  
Eliashberg Theory ◽  
Quantum Critical ◽  
Quantum Critical Behavior

DOES THE HEAVY ELECTRON MAINTAIN ITS INTEGRITY AT QUANTUM CRITICAL POINT?

2002 ◽  
Vol 16 (20n22) ◽  
pp. 2991-2991
Author(s):  
P. COLEMAN
Keyword(s):  
Critical Point ◽  
Density Wave ◽  
Quantum Critical Point ◽  
Spin Density Wave ◽  
Electron Mass ◽  
Heavy Electron ◽  
Heavy Fermion Materials ◽  
Quantum Critical ◽  
Composite Nature ◽  
Quantum Critical Behavior

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.

Quantum critical point and unusual phase diagram in the itinerant-electron metamagnet UCoAl

2015 ◽  
Vol 92 (3) ◽  
Author(s):  
N. Kimura ◽  
N. Kabeya ◽  
H. Aoki ◽  
K. Ohyama ◽  
M. Maeda ◽  
...  
Keyword(s):  
Phase Diagram ◽  
Critical Point ◽  
Quantum Critical Point ◽  
Itinerant Electron ◽  
Quantum Critical

scholarly journals QUANTUM CRITICAL BEHAVIOR IN KONDO SYSTEMS

1999 ◽  
Vol 13 (18) ◽  
pp. 2331-2342 ◽  
Author(s):  
QIMIAO SI ◽  
J. LLEWEILUN SMITH ◽  
KEVIN INGERSENT
Keyword(s):  
Critical Point ◽  
Critical Behavior ◽  
Density Wave ◽  
Mean Field ◽  
Kondo Lattice ◽  
Impurity Model ◽  
Operational Test ◽  
Mean Field Equations ◽  
Quantum Critical ◽  
Quantum Critical Behavior

This article briefly reviews three topics related to the quantum critical behavior of certain heavy-fermion systems. First, we summarize an extended dynamical mean-field theory for the Kondo lattice, which treats on an equal footing the quantum fluctuations associated with the Kondo and RKKY couplings. The resulting dynamical mean-field equations describe a Kondo impurity model with an additional coupling to vector bosons. Two types of quantum phase transition appear to be possible within this approach — the first a conventional spin-density-wave transition, the second driven by local physics. For the second type of transition to be realized, the effective impurity model must have a quantum critical point exhibiting an anomalous local spin susceptibility. In the second part of the paper, such a critical point is shown to occur in two variants of the Kondo impurity problem. Finally, we propose an operational test for the existence of quantum critical behavior driven by local physics. Neutron scattering results suggest that CeCu 6-x Au x passes this test.

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