Non-Fermi liquid states in the pressurized $CeC{u}_2(S{i}_{1-x}G{e}_x{)}_2$ system: two critical points

Abstract

In the archetypal strongly correlated electron superconductor CeCu${}_2$Si${}_2$ and its Ge-substituted alloys CeCu${}_2$(Si${}_{1-x}$Ge${}_x$)${}_2$ two quantum phase transitions -- one magnetic and one of so far unknown origin -- can be crossed as a function of pressure \cite{Yuan 2003a}. We examine the associated anomalous normal state by detailed measurements of the low temperature resistivity ($\rho$) power law exponent $\alpha$. At the lower critical point (at $p_{c1}$, $1\le \alpha \le 1.5$) $\alpha$ depends strongly on Ge concentration $x$ and thereby on disorder level, consistent with a Hlubina-Rice-Rosch scenario of critical scattering off antiferromagnetic fluctuations. By contrast, $\alpha$ is independent of $x$ at the upper quantum phase transition (at $p_{c2}$, $\alpha \simeq 1$), suggesting critical scattering from local or Q=0 modes, in agreement with a density/valence fluctuation approach.

4 pages, including 4 figures. New results added. Significant changes on the text and Fig. 4

References in corpus (3)

• Signatures of valence fluctuations in CeCu2Si2 under high pressure
• Interplay of disorder and spin fluctuations in the resistivity near a quantum critical point
• Huge Enhancement of Impurity Scattering due to Critical Valence Fluctuations in a Ce-Based Heavy Electron System

Cited by in corpus (28)

• Fermi-liquid instabilities at magnetic quantum phase transitions
• Reversible Tuning of the Heavy Fermion Ground State in CeCoIn${}_5$
• Topology of the Fermi Surface Beyond the Quantum Critical Point
• Multiple quantum phase transitions and superconductivity in Ce-based heavy fermions
• Superconductivity in Ce- and U-based "122" heavy-fermion compounds
• Valence Fluctuations Revealed by Magnetic Field Scan: Comparison with Experiments in YbXCu_4 (X=In, Ag, Cd) and CeYIn_5 (Y=Ir, Rh)
• Singularity of the London penetration depth at quantum critical points in superconductors
• Gap symmetry of the heavy fermion superconductor CeCu${}_2$Si${}_2$ at ambient pressure
• Heavy Fermion superconductor CeCu${}_2$Si${}_2$ under high pressure: multiprobing the valence crossover
• Quantum phase transition in the heavy-fermion compound YbIr${}_2$Si${}_2$
• Unconventional fully-gapped superconductivity in the heavy-fermion metal CeCu${}_2$Si${}_2$
• CeIrIn5: Superconductivity on a Magnetic Instability
• Two types of superconducting domes in unconventional superconductors
• Superconductivity modulated by structural phase transitions in pressurized vanadium-based kagome metals
• Pressure-induced change of the pairing symmetry in superconducting CeCu2Si2
• Two Fermi surface states and two $T_{\mathrm{c}}$-rising mechanisms revealed by transport properties in $R$FeP${}_{1-x}$As${}_x$O${}_{0.9}$F${}_{0.1}$ ($R$=La, Pr and Nd)
• Crossover from a heavy fermion to intermediate valence state in noncentrosymmetric Yb2Ni12(P,As)7
• Heavily Hydride-ion-doped 1111-type Iron-based Superconductors: Synthesis, Physical Properties and Electronic Structure
• Superconductivity of cerium under pressures up to 54GPa
• Quantum criticality and first-order transitions in the extended periodic Anderson model
• Lattice models for Non-Fermi Liquids with Tunable Transport Scalings
• Crossover between Fermi liquid and non-Fermi liquid behavior in the non-centrosymmetric compound Yb${}_2$Ni${}_{12}$P${}_7$
• Influence of Quantum Critical Point of First Order Valence Transition on Ce- and Yb-Based Heavy Fermions
• Momentum distribution functions in a one-dimensional extended periodic Anderson model
• Electronic Landscape of Ce-based Intermetallics: CeCu${}_2$Si${}_2$ at an Extreme
• Change of Fermi surface states related with two different $T_{\mathrm{c}}$-raising mechanisms in iron pnictide superconductor
• Multiband electronic transport in $\alpha$-Yb${}_{1-x}$Sr${}_x$AlB${}_4$ [x = 0, 0.19(3)] single crystals
• Emergent magnetism, heavy electrons and pressure-induced reentrant superconductivity in the iron substituted 4d transition-metal sulfides