The evolution of the Non-Fermi Liquid behavior of BaVS$_3$ under high pressure

TL;DR

This study investigates how the non-Fermi liquid behavior of BaVS$_3$ evolves under high pressure, revealing a crossover to Fermi-liquid behavior linked to pseudogap suppression and charge fluctuations.

Contribution

It provides detailed experimental insights into the pressure-induced transition from NFL to FL behavior in BaVS$_3$, highlighting the role of pseudogaps and charge fluctuations.

Findings

Resistivity follows a $T^n$ dependence with $n$ increasing from 1.5 to 2 with pressure.

A characteristic magnetic field of about 12 T suppresses the pseudogap.

The NFL to FL crossover is associated with pseudogap evolution and charge density wave fluctuations.

Abstract

Temperature, pressure, and magnetic field dependencies of the resistivity of BaVS$_3$ were measured above the critical pressure of $p_{cr}$=2 GPa, which is associated with the zero temperature insulator-to-metal (MI) transition. The resistivity exhibits the $T^n$ temperature dependence below $T_g\approx$15 K, with $n$ of 1.5 at $p_{cr}$, which increases continuously with pressure towards 2. This is interpreted as a crossover from non-Fermi (NFL) to Fermi-liquid (FL) behavior. Although the spin configuration of the $e_g$ electrons influences the charge propagation, the NFL behavior is attributed to the pseudogap that appears in the single particle spectrum of the $d_z^2$ electrons related to large quasi-one dimensional (Q-1d) 2$k_F$-CDW fluctuations. The non-monotonic magnetic field dependence of $\Delta$$\rho$/$\rho$ reveals a characteristic field $B_0\approx$12 T attributed to the full suppression of the pseudogap.