Stabilization of a honeycomb lattice of IrO6 octahedra by formation of ilmenite-type superlattices in MnTiO3

Abstract

In quantum spin liquid research, thin films are an attractive arena that enables the control of magnetic interactions via epitaxial strain and two-dimensionality, which are absent in bulk crystals. Here, as a promising candidate for the development of quantum spin liquids in thin films, we propose a robust ilmenite-type oxide with a honeycomb lattice of edge-sharing IrO 6 octahedra artificially stabilised by superlattice formation using the ilmenite-type antiferromagnetic oxide MnTiO 3. Stabilised sub-unit-cell-thick Mn-Ir-O layers are isostructural to MnTiO 3 and have an atomic arrangement corresponding to ilmenite-type MnIrO 3. By performing spin Hall magnetoresistance measurements, we observe 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 contribute to the development of twodimensional Kitaev candidate materials, accelerating the discovery of exotic physics and applications specific to quantum spin liquids.

Asymmetric modulation of Majorana excitation spectra and nonreciprocal thermal transport in the Kitaev spin liquid under a staggered magnetic field

“…Note that van der Waals heterostructures of atomically thin α-RuCl 3 and graphene have been fabricated [36][37][38][39], which would be extended to the current situation. Besides, a superstructure of an ilmenite MnTiO 3 including IrO 6 honeycomb layers [40,41] could be such a platform, where the antiferromagnetic moment in MnTiO 3 can be regarded as a staggered internal magnetic field acting on the possible Kitaev spin liquid in the IrO 6 honeycomb layers [42][43][44]. In such situations, however, the magnon excitations in the antiferromagnet can contribute to the thermal transport.…”

Electronic and magnetic properties of iridium ilmenites $A$IrO$_3$ ($A=$ Mg, Zn, and Mn)

“…In this paper, we investigate the electronic band structures of MgIrO 3 and ZnIrO 3 by using the first-principles calculations with the fully-relativistic local density approximation including effective onsite Coulomb interactions, called the LDA+SOC+U method. For comparison, we study the well-known antiferromagnetic insulator MnTiO 3 and a fictitious crystal MnIrO 3 whose local stacking structure was recently elaborated in a superlattice with MnTiO 3 [40]. We find that MgIrO dospin with effective magnetic moment j eff = 1/2.…”