Erasable superconductivity in topological insulator Bi2Se3 induced by voltage pulse

TL;DR

This paper reports the discovery of reversible, voltage pulse-induced superconductivity in topological insulator Bi2Se3, with potential implications for quantum device design and topological superconductivity research.

Contribution

It demonstrates a novel method to induce and erase superconductivity in Bi2Se3 using voltage pulses and thermal cycles, revealing new control over topological superconducting states.

Findings

Superconductivity observed via Andreev reflection and resistance drop.

Superconductivity can be erased by warming to 300 K.

Superconductivity can be re-induced by voltage pulses at low temperature.

Abstract

Three-dimensional topological insulators (TIs) attract much attention due to its topologically protected Dirac surface states. Doping into TIs or their proximity with normal superconductors can promote the realization of topological superconductivity(SC) and Majorana fermions with potential applications in quantum computations. Here, an emergent superconductivity was observed in local mesoscopic point-contacts on the topological insulator Bi2Se3 by applying a voltage pulse through the contacts, evidenced by the Andreev reflection peak in the point-contact spectra and a visible resistance drop in the four-probe electrical resistance measurements. More intriguingly, the superconductivity can be erased with thermal cycles by warming up to high temperatures (300 K) and induced again by the voltage pulse at the base temperature (1.9 K), suggesting a significance for designing new types of quantum devices. Nematic behaviour is also observed in the superconducting state, similar to the case of CuxBi2Se3 as topological superconductor candidates.