Dual gate control of bulk transport and magnetism in the spin-orbit insulator Sr2IrO4

TL;DR

This paper demonstrates the dual control of electronic transport and magnetic properties in Sr2IrO4 using an ionic liquid gate, revealing strong coupling among charge, orbital, and spin degrees of freedom in this spin-orbit insulator.

Contribution

It introduces a novel ionic liquid gating method to simultaneously modulate transport and magnetism in Sr2IrO4, highlighting the coupling of physical properties in spin-orbit coupled oxides.

Findings

Effective gate control of conduction and magnetism achieved.

Confirmation of strong coupling among charge, orbital, and spin degrees of freedom.

Potential for exploring emergent quantum phases in iridates.

Abstract

The 5d iridates have been the subject of much recent attention due to the predictions of a large array of novel electronic phases driven by twisting strong spin-orbit coupling and Hubbard correlation. As a prototype, the single layered perovskite Sr2IrO4 was first revealed to host a Jeff=1/2 Mott insulating state. In this material, the approximate energy scale of a variety of interactions, involving spin-orbit coupling, magnetic exchange interaction, and the Mott gap, allows close coupling among the corresponding physical excitations, opening the possibility of cross control of the physical properties. Here, we experimentally demonstrate the effective gate control of both the transport and magnetism in a Sr2IrO4-based field effect transistor using an ionic liquid dielectric. This approach could go beyond the surface-limited field effect seen in conventional transistors, reflecting the unique aspect of the Jeff=1/2 state. The simultaneous modulation of conduction and magnetism confirms the proposed intimate coupling of charge, orbital, and spin degrees of freedom in this oxide. These phenomena are probably related to an enhanced deviation from the ideal Jeff=1/2 state due to the gate-promoted conduction. The present work would have important implications in modelling the unusual physics enabled by strong spin-orbit coupling, and provides a new route to explore those emergent quantum phases in iridates.