QUANTUM CRITICAL FLUCTUATIONS IN HEAVY FERMION COMPOUNDS

2002 ◽  
Vol 16 (20n22) ◽  
pp. 3031-3036 ◽  
Author(s):  
A. SCHROEDER ◽  
G. AEPPLI ◽  
P. COLEMAN ◽  
R. RAMAZASHVILI ◽  
R. COLDEA ◽  
...  
Keyword(s):  
Neutron Scattering ◽  
Heavy Fermion ◽  
Magnetic Moments ◽  
Quantum Critical Point ◽  
Electron System ◽  
Spin Fluctuations ◽  
Scattering Data ◽  
Critical Fluctuations ◽  
Conventional View ◽  
Quantum Critical

The electronic properties of heavy fermion alloys are dominated by spin fluctuations which are expected to become critical when tuned by pressure to a quantum critical point (QCP), entering a magnetic ordered state. Apart from the onset of exotic superconductivity, unexpected "normal conducting" behavior is found close to the QCP, which does not seem only to escape the conventional view of metals (Fermi liquids) but also the "conventional view" of an antiferromagnetic quantum phase transition in these f-metals. So far only few compounds have been investigated by neutron scattering to directly reveal the critical fluctuations spectrum. In CeCu 59 Au 01 the fluctuations develop an unusual energy dependence, characterized by an exponent α = 0.75, which persist over the entire Brillouin zone, provoking an unexpected local non Fermi liquid behavior. The same unusual exponent derived from E/T scaling determines the H/T scaling of the uniform magnetization. Recent neutron scattering data in magnetic fields further confirm this picture of nearly free local magnetic moments (modified by α) emerging at the antiferromagnetic QCP in this strongly correlated electron system.

The extent of quantum critical fluctuations into the heavy-fermion phase: A neutron scattering study of Ce(Ru1−xFex)2Ge2

2005 ◽  
Vol 97 (10) ◽  
pp. 10A909 ◽  
Author(s):  
W. Montfrooij ◽  
M. C. Aronson ◽  
B. D. Rainford ◽  
J. A. Mydosh ◽  
R. Hendrikx ◽  
...  
Keyword(s):  
Neutron Scattering ◽  
Heavy Fermion ◽  
Critical Fluctuations ◽  
Scattering Study ◽  
Quantum Critical ◽  
Neutron Scattering Study

scholarly journals Possible quantum critical behavior revealed by the critical current density of hole doped high-Tc cuprates in comparison to heavy fermion superconductors

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
S. H. Naqib ◽  
R. S. Islam
Keyword(s):  
Critical Current Density ◽  
Copper Oxide ◽  
Critical Point ◽  
Critical Current ◽  
Current Density ◽  
Heavy Fermion ◽  
Quantum Critical Point ◽  
Oxide Superconductors ◽  
Copper Oxide Superconductors ◽  
Quantum Critical

Abstract The superconducting critical current density, Jc, in hole doped cuprates show strong dependence on the doped hole content, p, within the copper oxide plane(s). The doping dependent Jc mainly exhibits the variation of the intrinsic depairing critical current density as p is varied. Jc(p) tends to peak at p ~ 0.185 in copper oxide superconductors. This particular value of the hole content, often termed as the critical hole concentration, has several features putative to a quantum critical point (QCP). Very recently, the pressure dependences of the superconducting transition temperature (Tc) and the critical current (Ic) in pure CeRhIn5 and Sn doped CeRhIn5 heavy fermion compounds have been reported (Nature Communications (2018) 9:44, 10.1038/s41467-018-02899-5). The critical pressure demarcates an antiferromagnetic quantum critical point where both Tc and Ic are maximized. We have compared and contrasted this behavior with those found for Y1−xCaxBa2Cu3O7−δ in this brief communication. The resemblance of the systematic behavior of the critical current with pressure and hole content between heavy fermion systems and hole doped cuprates is significant. This adds to the circumstantial evidence that quantum critical physics probably plays a notable role behind the unconventional normal and superconducting state properties of copper oxide superconductors.

scholarly journals Singular charge fluctuations at a magnetic quantum critical point

Science ◽  
2020 ◽  
Vol 367 (6475) ◽  
pp. 285-288 ◽  
Author(s):  
L. Prochaska ◽  
X. Li ◽  
D. C. MacFarland ◽  
A. M. Andrews ◽  
M. Bonta ◽  
...  
Keyword(s):  
Optical Conductivity ◽  
Heavy Fermion ◽  
Molecular Beam ◽  
Cuprate Superconductors ◽  
Quantum Critical Point ◽  
Charge Fluctuations ◽  
Quantum Matter ◽  
Temperature Scaling ◽  
Landau Quantum ◽  
Quantum Critical

Strange metal behavior is ubiquitous in correlated materials, ranging from cuprate superconductors to bilayer graphene, and may arise from physics beyond the quantum fluctuations of a Landau order parameter. In quantum-critical heavy-fermion antiferromagnets, such physics may be realized as critical Kondo entanglement of spin and charge and probed with optical conductivity. We present terahertz time-domain transmission spectroscopy on molecular beam epitaxy–grown thin films of YbRh2Si2, a model strange-metal compound. We observed frequency over temperature scaling of the optical conductivity as a hallmark of beyond-Landau quantum criticality. Our discovery suggests that critical charge fluctuations play a central role in the strange metal behavior, elucidating one of the long-standing mysteries of correlated quantum matter.

Pressure-induced quantum critical point in the heavy fermion compound

2005 ◽  
Vol 359-361 ◽  
pp. 65-67 ◽  
Author(s):  
G. Oomi ◽  
M. Ohashi ◽  
Y. Uwatoko ◽  
I. Satoh ◽  
T. Komatsubara
Keyword(s):  
Critical Point ◽  
Heavy Fermion ◽  
Quantum Critical Point ◽  
Heavy Fermion Compound ◽  
Quantum Critical

scholarly journals Quantum critical fluctuations in the heavy fermion compound Ce(Ni0.935Pd0.065)2Ge2

2014 ◽  
Vol 27 (1) ◽  
pp. 015602 ◽  
Author(s):  
C H Wang ◽  
L Poudel ◽  
A E Taylor ◽  
J M Lawrence ◽  
A D Christianson ◽  
...  
Keyword(s):  
Heavy Fermion ◽  
Critical Fluctuations ◽  
Heavy Fermion Compound ◽  
Quantum Critical

scholarly journals Field-Induced Quantum Critical Point and Nodal Superconductivity in the Heavy-Fermion SuperconductorCe2PdIn8

2011 ◽  
Vol 1 (1) ◽  
Author(s):  
J. K. Dong ◽  
H. Zhang ◽  
X. Qiu ◽  
B. Y. Pan ◽  
Y. F. Dai ◽  
...  
Keyword(s):  
Critical Point ◽  
Heavy Fermion ◽  
Quantum Critical Point ◽  
Quantum Critical

Heavy-fermion quantum critical point behavior in CeNi9Ge4

2004 ◽  
Vol 272-276 ◽  
pp. 227-228 ◽  
Author(s):  
H Michor ◽  
E Bauer ◽  
C Dusek ◽  
G Hilscher ◽  
P Rogl ◽  
...  
Keyword(s):  
Critical Point ◽  
Heavy Fermion ◽  
Quantum Critical Point ◽  
Quantum Critical

scholarly journals Quantum Critical Point of an Itinerant Antiferromagnet in a Heavy Fermion

2006 ◽  
Vol 96 (1) ◽  
Author(s):  
Hiroaki Kadowaki ◽  
Yoshikazu Tabata ◽  
Masugu Sato ◽  
Naofumi Aso ◽  
Stephane Raymond ◽  
...  
Keyword(s):  
Critical Point ◽  
Heavy Fermion ◽  
Quantum Critical Point ◽  
Quantum Critical
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