Design of Chern Insulating Phases in Honeycomb Lattices

TL;DR

This paper explores the design of Chern insulators in honeycomb lattices, identifying conditions under which realistic Chern insulating phases can be realized in multiorbital 4d and 5d oxide materials.

Contribution

It demonstrates a design approach for Chern insulators in honeycomb lattices, focusing on multiorbital 4d and 5d oxides, advancing the search for magnetic topological insulators.

Findings

Realistic prediction of Chern insulating ground states in 4d and 5d oxides

Identification of key energy scales influencing Chern phase stability

Design principles for achieving Chern insulators in honeycomb lattices

Abstract

The search for robust examples of the magnetic version of topological insulators, referred to as quantum anomalous Hall insulators or simply Chern insulators, so far lacks success. Our groups have explored two distinct possibilities based on multiorbital 3d oxide honeycomb lattices. Each has a Chern insulating phase near the ground state, but materials parameters were not appropriate to produce a viable Chern insulator. Further exploration of one of these classes, by substituting open shell 3d with 4d and 5d counterparts, has led to realistic prediction of Chern insulating ground states. Here we recount the design process, discussing the many energy scales that are active in participating (or resisting) the desired Chern insulator phase.