# Majorana corner and hinge modes in second-order topological insulator-superconductor heterostructures

## TL;DR

This paper explores second-order topological insulator/superconductor heterostructures, revealing they can host Majorana modes without special pairings or magnetic fields, advancing potential platforms for quantum computing.

## Contribution

It introduces second-order topological insulator/superconductor heterostructures as natural realizations of second-order topological superconductors hosting Majorana modes.

## Key findings

- Realization of Majorana corner modes in 2D heterostructures
- Chiral Majorana hinge modes in 3D heterostructures
- No need for special pairings or magnetic fields

## Abstract

As platforms of Majorana modes, topological insulator (quantum anomalous Hall insulator)/superconductor (SC) heterostructures have attracted tremendous attention over the past decade. Here we substitute the topological insulator by its higher-order counterparts. Concretely, we consider second-order topological insulators (SOTIs) without time-reversal symmetry and investigate SOTI/SC heterostructures in both two and three dimensions. Remarkably, we find that such novel heterostructures provide natural realizations of second-order topological superconductors (SOTSCs) which host Majorana corner modes in two dimensions and chiral Majorana hinge modes in three dimensions. As here the realization of SOTSCs requires neither special pairings nor magnetic fields, such SOTI/SC heterostructures are outstanding platforms of Majorana modes and may have wide applications in future.