Topological insulators from complex orbital order in transition-metal oxides heterostructures

TL;DR

This paper demonstrates that topological insulators can be realized in transition-metal oxide heterostructures through local electron interactions, leading to spontaneous complex orbital order and stable topological phases.

Contribution

It provides theoretical evidence that two-dimensional topological insulators can be stabilized in oxide heterostructures via local interactions, highlighting the role of orbital order.

Findings

Topological phases are stabilized in (111) heterostructures of transition-metal oxides.

Spontaneous complex orbital order accompanies the topological phases.

The stability of these phases is analyzed against various competing interactions.

Abstract

Topological band insulators which are dynamically generated by electron-electron interactions have been the- oretically proposed in two and three dimensional lattice models. We present evidence that the two-dimensional version can be stabilized in digital (111) heterostructures of transition-metal oxides as a result of purely local interactions. The topological phases are accompanied by spontaneous ordering of complex orbitals and we discuss their stability with respect to the Hund's rule coupling, Jahn-Teller interaction and inversion symmetry breaking terms. As main competitors we identify spin-nematic and magnetic phases.