Molecular Beam Epitaxy of a Half-Heusler Topological Superconductor Candidate YPtBi

TL;DR

This paper reports the successful growth of high-quality epitaxial thin films of YPtBi, enabling advanced experiments to explore its potential topological superconductivity, which was previously limited by bulk crystal studies.

Contribution

It introduces a method to produce high-quality YPtBi thin films via molecular beam epitaxy, facilitating detailed investigation of its topological superconducting properties.

Findings

Epitaxial YPtBi(111) films grown successfully

Superconducting properties consistent with bulk crystals

Surface protection enables lithography for further studies

Abstract

The search for topological superconductivity has motivated investigations into materials that combine topological and superconducting properties. The half-Heusler compound YPtBi appears to be such a material, however experiments have thus far been limited to bulk single crystals, drastically limiting the scope of available experiments. This has made it impossible to investigate the potential topological nature of the superconductivity in this material. Experiments to access details about the superconducting state require sophisticated lithographic structures, typically based on thin films. Here we report on the establishment of high crystalline quality epitaxial thin films of YPtBi(111), grown using molecular beam epitaxy on Al2O3(0001) substrates. A robust superconducting state is observed, with both critical temperature and critical field consistent with that previously reported for bulk crystals. Moreover we find that AlOx capping sufficiently protects the sample surface from degradation to allow for proper lithography. Our results pave a path towards the development of advanced lithographic structures, that will allow the exploration of the potentially topological nature of superconductivity in YPtBi.