New Quantum Criticality Revealed under Pressure

Abstract

Unconventional quantum critical phenomena observed in Yb-based periodic crystals such as YbRh${}_2$Si${}_2$ and $\beta$-YbAlB${}_4$ have been one of the central issues in strongly correlated electron systems. The common criticality has been discovered in quasicrystal Yb${}_{15}$Au${}_{51}$Al${}_{34}$, which surprisingly persists under pressure at least up to $P=1.5$ GPa. The $T/H$ scaling where the magnetic susceptibility can be expressed as a single scaling function of the ratio of temperature $T$ and magnetic field $H$ has been discovered in the quasicrystal, which is essentially the same as that observed in $\beta$-YbAlB${}_4$. Recently, the $T/H$ scaling as well as the common criticality has been also observed even in the approximant crystal Yb${}_{14}$Au${}_{51}$Al${}_{35}$ under pressure. The theory of critical Yb-valence fluctuation gives a natural explanation for these striking phenomena in a unified way.

17 pages, 5 figures, Invited review paper in the 17th International Conference on High Pressure in Semiconductor Physics (HPSP-17) & Workshop on High-pressure Study on Superconducting (WHS)

References in corpus (14)

• Signatures of valence fluctuations in CeCu2Si2 under high pressure
• Quantum critical state in a magnetic quasicrystal
• Quantum Valence Criticality as Origin of Unconventional Critical Phenomena
• Roles of Critical Valence Fluctuations in Ce- and Yb-Based Heavy Fermion Metals
• Superconductivity emerging near quantum critical point of valence transition
• Magnetic-Field Control of Quantum Critical Points of Valence Transition
• Non-Fermi-Liquid Behavior in Metallic Quasicrystals with Local Magnetic Moments
• Valence Fluctuations Revealed by Magnetic Field Scan: Comparison with Experiments in YbXCu_4 (X=In, Ag, Cd) and CeYIn_5 (Y=Ir, Rh)
• Pressure-Induced Valence Crossover and Novel Metamagnetic Behavior near the Antiferromagnetic Quantum Phase Transition of YbNi${}_3$Ga${}_9$
• Unconventional Quantum Criticality due to Critical Valence Transition
• New Universality Class of Quantum Criticality in Ce- and Yb-based Heavy Fermions
• T/B Scaling in beta-YbAlB4
• Distributed Hybridization Model for Quantum Critical Behavior in Magnetic Quasicrystals
• Wide Quantum Critical Region of Valence Fluctuations: Origin of Robust Quantum Criticality in Quasicrystal Yb15Al34Au51 under Pressure