Quantum Criticality Beneath the Superconducting Dome in β-YbAlB4

TMU International Symposium on "New Quantum Phases Emerging from Novel Crystal Structure"

Tomita, T.^1 ; Kuga, K.^2 ; Uwatoko, Y.^1 ; Nakatsuji, S.^1

Institute for Solid State Physics, University of Tokyo, Kashiwanoha, Kashiwa, Chiba

277-8581, Japan^1

RIKEN SPring-8 Center, Sayo, Hyogo

679-5148, Japan^2

关键词: Ambient pressures;    Applied pressure;    Electron systems;    High quality single crystals;    Non-Fermi liquids;    Quantum critical points;    Quantum criticality;    Temperature phase;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/683/1/012007/pdf
DOI  :  10.1088/1742-6596/683/1/012007

来源: IOP

【 摘 要 】

Yb-based heavy fermion superconductor β-YbAlB4at 0 K and 0 T at ambient pressure is located near the quantum critical point with strong mixed valiancy. In this type of Yb electron system, we expect that the magnetic order connected to the quantum critical point derives from the applied pressure. We built a pressure-temperature phase diagram for β-YbAlB4by measuring the electrical resistivity of high quality single crystal at temperatures down to 40 mK under an applied pressure. A strange metal region appeared, showing non-Fermi liquid ρabα T1.5behavior, which is stable with applied pressure up to 0.4 GPa, even when below the superconducting dome excluded by a magnetic field of 0.1 T. By increasing of pressure above 2.5 GPa, a magnetic order is first generated. Such ambient quantum criticality/superconductivity is unconventional and is detached from the magnetic order.