Quantum critical phase in BaVS$_3$

TL;DR

This study investigates the high-pressure metallic phase of BaVS$_3$, revealing a non-Fermi liquid regime with magnetic ordering near the insulator-metal boundary, and draws parallels with non-conventional itinerant magnets.

Contribution

It provides detailed experimental evidence of a non-Fermi liquid phase and magnetic ordering in BaVS$_3$ under high pressure, highlighting its analogy with non-conventional itinerant magnets.

Findings

Extended non-Fermi liquid regime with resistivity exponent 1.5 to 2

Magnetic ordering indicated by hysteresis near the insulator-metal boundary

Transition to Fermi liquid behavior around 2.7 GPa

Abstract

We study the high-pressure metallic phase of high-purity single crystals of BaVS$_3$ by measuring the temperature, pressure, and magnetic field dependence of the resistivity. Above the critical pressure of $p_{\rm cr}=1.97$GPa an extended non-Fermi liquid $p-T$ regime emerges with resistivity exponent $1.5 \le n<2$, crossing over to a FL only around $p=2.7$GPa. A hysteretic feature indicates that close to the insulator--metal boundary, the system is magnetically ordered. Our findings reveal a close analogy between the extended partially ordered NFL state of non-conventional itinerant magnets and the corresponding state of BaVS$_3