Superconductivity and non-metallicity induced by doping the topological insulators Bi2Se3 and Bi2Te3

TL;DR

This paper demonstrates how doping and intercalation can tune the electronic properties of topological insulators Bi2Se3 and Bi2Te3, inducing superconductivity and non-metallicity, which are promising for quantum applications.

Contribution

It introduces doping and intercalation methods to control conductivity and induce superconductivity in Bi2Se3 and Bi2Te3 topological insulators, advancing material engineering techniques.

Findings

Ca-doping suppresses bulk conductivity in Bi2Se3

Copper intercalation induces superconductivity in Bi2Se3 (~3.8 K)

Te content variation turns Bi2Te3 into a non-metallic state with slight superconductivity (~5.5 K)

Abstract

We show that by Ca-doping the Bi2Se3 topological insulator, the Fermi level can be fine tuned to fall inside the band gap and therefore suppress the bulk conductivity. Non-metallic Bi2Se3 crystals are obtained. On the other hand, the Bi2Se3 topological insulator can also be induced to become a bulk superconductor, with Tc ~ 3.8 K, by copper intercalation in the van der Waals gaps between the Bi2Se3 layers. Likewise, an as-grown crystal of metallic Bi2Te3 can be turned into a non-metallic crystal by slight variation of the Te content. The Bi2Te3 topological insulator shows small amounts of superconductivity with Tc ~ 5.5 K when reacted with Pd to form materials of the type PdxBi2Te3.