Stabilization of a honeycomb lattice of IrO$_6$ octahedra in superlattices with ilmenite-type MnTiO$_3$

TL;DR

This paper reports the stabilization of a honeycomb lattice of IrO$_6$ octahedra in superlattices with MnTiO$_3$, creating a new material platform potentially suitable for quantum spin liquid research.

Contribution

It introduces a novel superlattice structure combining IrO$_6$ and MnTiO$_3$ with a honeycomb lattice, not previously realized, for exploring quantum spin liquids.

Findings

Antiferromagnetic order in Mn sublattice is suppressed in the superlattice.

The stabilized structure is isostructural to MnTiO$_3$ but with a honeycomb IrO$_6$ lattice.

Potential for creating two-dimensional Kitaev materials.

Abstract

In the quest for quantum spin liquids, thin films are expected to open the way for the control of intricate magnetic interactions in actual materials by exploiting epitaxial strain and two-dimensionality. However, materials compatible with conventional thin-film growth methods have largely remained undeveloped. As a promising candidate towards the materialization of quantum spin liquids in thin films, we here present a robust ilmenite-type oxide with a honeycomb lattice of edge-sharing IrO$_6$ octahedra artificially stabilized by superlattice formation with an ilmenite-type antiferromagnetic oxide MnTiO$_3$. The stabilized sub-unit-cell-thick Mn-Ir-O layer is isostructural to MnTiO$_3$, having the atomic arrangement corresponding to ilmenite-type MnTiO$_3$ not discovered yet. By spin Hall magnetoresistance measurements, we found that antiferromagnetic ordering in the ilmenite Mn sublattice is suppressed by modified magnetic interactions in the MnO$_6$ planes via the IrO$_6$ planes. These findings lay the foundation for the creation of two-dimensional Kitaev candidate materials, accelerating the discovery of exotic physics and applications specific to quantum spin liquids.