Topological superconductivity and Majorana bound states at the LaAlO₃/SrTiO₃ interface

¹ Department of Physics, Indian Institute of Technology Kharagpur - Kharagpur, W.B. 721302, India
² Centre for Theoretical Studies, Indian Institute of Technology Kharagpur - Kharagpur, W.B. 721302, India

Received: 27 September 2014
Accepted: 29 November 2014

Abstract

The interface between two band insulators LaAlO₃ and SrTiO₃ exhibits low-temperature superconductivity coexisting with an in-plane ferromagnetic order. We show that topological superconductivity hosting Majorana bound states can be induced at the interface by applying a magnetic field perpendicular to the interface. We find that the dephasing effect of the in-plane magnetization on the topological superconducting state can be overcome by tuning a gate voltage. We analyze the vortex-core excitations showing the zero-energy Majorana bound states and the effect of non-magnetic disorder on them. Finally, we propose an experimental geometry where such topological excitations can be realized.