Higher-Order Topological Superconductivity and Electrically Tunable Majorana Corner Modes in Monolayer MnXPb$_2$ (X=Se, Te)-Pb Heterostructure

TL;DR

This paper proposes a new type of higher-order topological superconductor in MnXPb$_2$-Pb heterostructures, enabling electrically tunable Majorana corner modes for scalable quantum computing.

Contribution

It introduces a symmetry-enforced higher-order topological superconductivity platform based on antiferromagnetic topological insulators with electrical control of Majorana modes.

Findings

Majorana corner modes arise from boundary dichotomy in MnXPb$_2$-Pb heterostructures.

Superconducting proximity induces topological superconductivity at edges.

Electrical control enables manipulation of Majorana fusion and braiding.

Abstract

Higher-order topological superconductors host Majorana zero modes localized at corners or hinges, providing a promising route toward scalable and controllable Majorana networks without vortices or magnetic flux. Here we propose a symmetry-enforced higher-order topological superconductivity based on antiferromagnetic topological insulators, specifically realized in MnXPb$_2$ (X = Se, Te)-Pb heterostructure. We show that the intrinsic boundary dichotomy-gapless Dirac states protected by an effective time-reversal symmetry on antiferromagnetic edges and magnetic gaps on ferromagnetic edges-naturally generates Majorana corner modes as mass domain walls. Superconducting proximity converts the antiferromagnetic edges into one-dimensional topological superconductors, and the intersections between superconducting and magnetic edges bind Majorana zero modes as mass domain walls. Combining first-principles calculations with a calibrated effective boundary theory, we demonstrate robust corner localization and purely electrical control of Majorana fusion and braiding in a triangular geometry. Our results establish MnXPb$_2$ as experimentally promising platform for electrically programmable Majorana networks in two dimensions.