Intrinsically Interacting Higher-Order Topological Superconductors

TL;DR

This paper introduces a minimal lattice model for 2D interacting higher-order topological superconductors, revealing a transition from trivial to topological phases with Majorana corner modes, guided by a Lieb-Schultz-Mattis constraint.

Contribution

It provides the first explicit lattice model for interacting higher-order topological superconductors without free-fermion counterparts, demonstrating a novel phase transition.

Findings

Interaction induces a topological phase transition.

Majorana corner modes are numerically confirmed.

Model advances understanding of interacting higher-order topology.

Abstract

We propose a minimal interacting lattice model for two-dimensional class-$D$ higher-order topological superconductors with no free-fermion counterpart. A Lieb-Schultz-Mattis-type constraint is proposed and applied to guide our lattice model construction. Our model exhibits a trivial product ground state in the weakly interacting regime, whereas, increasing electron interactions provoke a novel topological quantum phase transition to a $D_4$-symmetric higher-order topological superconducting state. The symmetry-protected Majorana corner modes are numerically confirmed with the matrix-product-state technique. Our theory paves the way for studying interacting higher-order topology with explicit lattice model constructions.