Pressure-Induced Superconductivity in Topological Heterostructure (PbSe)5(Bi2Se3)6

TL;DR

This study demonstrates that applying high pressure to the topological heterostructure (PbSe)5(Bi2Se3)6 induces two distinct superconducting states, with critical temperatures reaching up to 6.0 K, linked to structural phase transitions.

Contribution

It is the first experimental demonstration of pressure-induced superconductivity and multiple superconducting phases in this topological heterostructure.

Findings

Superconductivity appears at 10 GPa with Tc ~ 4.6 K.

A second superconducting state emerges above 30 GPa with Tc up to 6.0 K.

Structural transitions correlate with the emergence of different superconducting states.

Abstract

Recently, the natural heterostructure of (PbSe)5(Bi2Se3)6 has been theoretically predicted and experimentally confirmed as a topological insulator. In this work, we induce superconductivity in (PbSe)5(Bi2Se3)6 by implementing high pressure. As increasing pressure up to 10 GPa, superconductivity with Tc ~ 4.6 K suddenly appears, followed by an abrupt decrease. Remarkably, upon further compression above 30 GPa, a new superconducting state arises, where pressure raises the Tc to an unsaturated 6.0 K within the limit of our research. Combining XRD and Raman spectroscopies, we suggest that the emergence of two distinct superconducting states occurs concurrently with the pressure-induced structural transition in this topological heterostructure (PbSe)5(Bi2Se3)6.