Superconductivity at Pd/Bi$_2$Se$_3$ Interfaces Due to Self-Formed PdBiSe Interlayers

TL;DR

This paper reports the discovery of superconductivity at Pd/Bi$_2$Se$_3$ interfaces caused by the formation of a PdBiSe interlayer, which could enable advanced topological quantum devices.

Contribution

It demonstrates that sputtering Pd on Bi$_2$Se$_3$ induces superconductivity via interfacial chemical reactions forming PdBiSe, a novel approach for topological insulator modification.

Findings

Superconductivity observed at Pd/Bi$_2$Se$_3$ interfaces.

Interfacial superconductivity due to Pd diffusion and reaction.

Formation of PdBiSe layer with T_c of 1.5 K.

Abstract

Understanding the physical and chemical processes at the interface of metals and topological insulators is crucial for developing the next generation of topological quantum devices. Here we report the discovery of robust superconductivity in Pd/Bi$_2$Se$_3$ bilayers fabricated by sputtering Pd on the surface of Bi$_2$Se$_3$. Through transmission electron microscopy measurements, we identify that the observed interfacial superconductivity originates from the diffusion of Pd into Bi$_2$Se$_3$. In the diffusion region, Pd chemically reacts with Bi$_2$Se$_3$ and forms a layer of PdBiSe, a known su-perconductor with a bulk transition temperature of 1.5 K. Our work provides a method for in-troducing superconductivity into Bi$_2$Se$_3$, laying the foundation for developing sophisticated Bi$_2$Se$_3$-based topological devices.