Pressure dependence of phase transitions in the quasi one-dimensional metal-insulator transition system beta-Na1/3V2O5

TL;DR

This study investigates how pressure influences phase transitions in the quasi-one-dimensional vanadium oxide beta-Na1/3V2O5, revealing different pressure sensitivities for various transitions and suggesting mechanisms like increased interchain coupling.

Contribution

It provides the first detailed analysis of pressure effects on multiple phase transitions in beta-Na1/3V2O5, including the newly observed transition at 222 K.

Findings

The transition at 240 K is pressure-independent.

The transition at ~222 K is newly reported and pressure-independent.

The metal-insulator transition shifts to lower temperatures with pressure.

Abstract

The pressure dependence of phase transitions in the quasi one-dimensional vanadium oxide $\beta$-Na$_{1/3}$V$_2$O$_5$ has been studied by magnetic susceptibility and electrical resistivity measurements. The pressure dependence of the various transition temperatures is quite differently. The transition at T=240 K, previously reported and attributed to ordering on Na sites, and a second transition at $T \approx 222$ K, reported here for the first time and attributed to a further increase of order on Na sites, are almost independent of pressure. On the other hand, the metal-insulator (MI) transition at $T_{MI}=130$ K shifts to lower temperatures, while the magnetic transition at $T_N=24$ K shifts to higher temperatures with increasing pressure. We discuss the different pressure dependencies of $T_{MI}$ and $T_N$ in terms of increasing interchain coupling and the MI transition to be of Peierls type.