Higher-order topological superconductivity in a topological metal 1T$^\prime$-MoTe$_2$

TL;DR

This paper develops a systematic strategy to identify and design materials exhibiting higher-order topological superconductivity, demonstrated by predicting MoTe$_2$ as a potential candidate hosting Majorana corner modes.

Contribution

The authors introduce a four-step mathematical strategy to guide the search for higher-order topological superconductors, applicable to various materials and symmetries.

Findings

Recipe for higher-order Tsc phases with inversion symmetry

Prediction of MoTe$_2$ as a candidate for higher-order Tsc

Strategy accelerates material discovery for higher-order Tsc phases

Abstract

One key challenge in the field of topological superconductivity (Tsc) has been the rareness of material realization. This is true not only for the first-order Tsc featuring Majorana surface modes, but also for the higher-order Tsc, which host Majorana hinge and corner modes. Here, we propose a four-step strategy that mathematically derives comprehensive guiding principles for the search and design for materials of general higher-order Tsc phases. Specifically, such recipes consist of conditions on the normal state and pairing symmetry that can lead to a given higher-order Tsc state. We demonstrate this strategy by obtaining recipes for achieving three-dimensional higher-order Tsc phases protected by the inversion symmetry. Following our recipe, we predict that the observed superconductivity in centrosymmetric MoTe$_2$ is a candidate for higher-order Tsc with corner modes. Our proposed strategy enables systematic materials search and design for higher-order Tsc, which can mobilize the experimental efforts and accelerate the material discovery for higher-order Tsc phases.