Topological insulator associated with quantum anomalous Hall phase in ferromagnetic perovskite superlattices

TL;DR

This paper predicts a ferromagnetic topological insulator with quantum anomalous Hall effect in LaAlO3/SrTiO3 superlattices, highlighting a new class of materials with potential spintronic applications.

Contribution

It identifies a specific superlattice structure exhibiting ferromagnetism and topologically non-trivial energy gap with quantized Hall conductivity without external magnetic fields.

Findings

(LaAlO3)10/(LaOsO3)2 shows ferromagnetic ground state.

System exhibits quantized Hall conductivity in the energy gap.

Estimated ferromagnetic transition temperature (Tc).

Abstract

We do a search for topological insulators which are associated with ferromagnetic ordering and show anomalous quantum Hall effect, among transition metal oxide superlattices taking the parent compounds as LaAlO3 and SrTiO3. Among the various superlattices which are studied here, (LaAlO3)10/(LaOsO3)2 exhibits a ferromagnetic ground state with a topologically non-trivial energy gap when a spin-orbit interaction is turned on. The study of transverse conductivity shows that the system has quantized Hall conductivity inside the topological energy gap without applying any external magnetic field. The ferromagnetic order parameters and the ordering temperature (Tc) have been estimated by taking a simple Heisenberg model of ferromagnetism.