Metallisation of the Mott Insulator Ca$_{2}$RuO$_{4}$ using Electric Double-Layer Gating

TL;DR

This study demonstrates that electric double-layer gating can induce metallisation in Ca₂RuO₄, a Mott insulator, through structural changes rather than surface effects, highlighting a potential method for controlling electronic phases.

Contribution

It shows that EDLG can switch Ca₂RuO₄ from insulator to metal via bulk structural changes, independent of current flow, which is a novel approach.

Findings

Resistance decreases by ~97% with positive gate voltage

Metallisation likely involves bulk structural change, not surface effects

Switching occurs only above +3 V gate voltage

Abstract

To verify whether the Mott insulator Ca2RuO4 can be switched by applying electric-field alone, regardless of current flow, we employ metallisation using electric double-layer gating (EDLG). The resistance change due to EDLG occurs only when positive gate-voltage above +3 V is applied. The amplitude of the reduction, reaching ~97% of the initial value, is difficult to interpret as surface metallisation and is likely related to structural change in bulk.