From Mott insulator to ferromagnetic metal: a pressure study of Ca$_{2}$RuO$_{4}$

TL;DR

This study investigates how applying pressure induces a transition from a Mott insulator to a ferromagnetic metal in Ca$_{2}$RuO$_{4}$, revealing a complex phase diagram with significant changes in electronic and magnetic properties.

Contribution

It provides the first detailed pressure-temperature phase diagram of Ca$_{2}$RuO$_{4}$, highlighting the pressure-induced insulator-metal and magnetic transitions and their relation to structural distortions.

Findings

Metal-insulator transition at 0.5 GPa

Transition from paramagnetic insulator to metallic state at 300K

Transition from antiferromagnetic insulator to ferromagnetic metal at low temperature

Abstract

We show that the pressure-temperature phase diagram of the Mott insulator Ca$_{2}$RuO$_{4}$ features a metal-insulator transition at 0.5GPa: at 300K from paramagnetic insulator to paramagnetic quasi-two-dimensional metal; at $T \leq$ 12K from antiferromagnetic insulator to ferromagnetic, highly anisotropic, three-dimensional metal. % We compare the metallic state to that of the structurally related p-wave superconductor Sr$_{2}$RuO$_{4}$, and discuss the importance of structural distortions, which are expected to couple strongly to pressure.