Resilient Growth of Highly Crystalline Topological Insulator-Superconductor Heterostructure Enabled by Ex-situ Nitride Film

TL;DR

This paper demonstrates a resilient, highly crystalline topological insulator-superconductor heterostructure using refractory TiN films, enabling practical device fabrication with air-stable superconducting layers.

Contribution

It introduces a novel ex-situ growth method for TI-SC heterostructures using TiN, eliminating the need for in-situ processes and enhancing air stability.

Findings

TiN (111) films serve as resilient superconducting layers

Successful recyclable growth of Bi2Se3 on TiN surface

TI-SC heterostructures compatible with device fabrication techniques

Abstract

Highly crystalline and easily feasible topological insulator-superconductor (TI-SC) heterostructures are crucial for the development of practical topological qubit devices. The optimal superconducting layer for TI-SC heterostructures should be highly resilient against external contaminations and structurally compatible with TIs. In this study, we provide a solution to this challenge by showcasing the growth of a highly crystalline TI-SC heterostructure using refractory TiN (111) as the superconducting layer. This approach can eliminate the need for in-situ cleaving or growth. More importantly, the TiN surface shows high resilience against contaminations during air exposure, as demonstrated by the successful recyclable growth of Bi2Se3. Our findings indicate that TI-SC heterostructures based on nitride films are compatible with device fabrication techniques, paving a path to the realization of practical topological qubit devices in the future.