Chiral Topological superconductivity in the OAI/SC/FMI heterostructure avoiding the subband problem

TL;DR

This paper proposes a new heterostructure setup using obstructed atomic insulators, superconductors, and ferromagnetic insulators to realize 2D chiral topological superconductivity and Majorana states, avoiding the subband problem.

Contribution

It introduces a novel OAI/SC/FMI heterostructure design that stabilizes multiple topological superconducting phases with large Rashba spin-orbit coupling and broad chemical potential range.

Findings

Multiple TSC phases with Chern numbers -1, -2, -3, 3 achieved

Analytical phase diagram constructed using a 2D BdG Hamiltonian

Heterostructure design expands applications of OAIs in topological quantum computing

Abstract

Implementing topological superconductivity (TSC) and Majorana states (MSs) is one of the most significant and challenging tasks in both fundamental physics and topological quantum computations. In this work, taking the obstructed atomic insulator (OAI) Nb3Br8, s-wave superconductor (SC) NbSe2 and ferromagnetic insulator (FMI) as example, we propose a new setup to realize the 2D chiral TSC and MSs in the OAI/SC/FMI heterostructure, which could avoid the subband problem effectively and has the advantage of huge Rashba spin-orbit coupling. As a result, the TSC phase can be stabilized in a wide region of chemical potential and Zeeman field, and four distinct TSC phases with superconducting Chern number N= -1, -2, -3, 3 can be achieved. Moreover, a 2D BdG Hamiltonian based on the triangular lattice of obstructed Wannier charge centers, combined with the s-wave superconductivity paring and Zeeman field, is constructed to understand the whole topological phase diagram analytically. These results expand the application of OAIs and pave a new way to realize the TSC and MSs with unique advantages.