Pressure-induced Superconductivity in Zintl Topological Insulator SrIn2As2

TL;DR

This study reveals that applying pressure to the Zintl topological insulator SrIn2As2 induces superconductivity while maintaining its topological surface states, offering insights into the interplay between topology and superconductivity.

Contribution

It provides the first experimental evidence of pressure-induced superconductivity in SrIn2As2 and demonstrates the coexistence of topological surface states with superconductivity.

Findings

Topological surface states confirmed by ARPES

Superconductivity emerges under high pressure

Pressure tunes electronic properties from semiconducting to metallic

Abstract

The Zintl compound AIn2X2 (A = Ca, Sr, and X = P, As), as a theoretically predicted new non-magnetic topological insulator, requires experiments to understand their electronic structure and topological characteristics. In this paper, we systematically investigate the crystal structures and electronic properties of the Zintl compound SrIn2As2 under both ambient and high-pressure conditions. Based on systematic angle-resolved photoemission spectroscopy (ARPES) measurements, we observed the topological surface states on its (001) surface as predicted by calculations, indicating that SrIn2As2 is a strong topological insulator. Interestingly, application of pressure effectively tuned the crystal structure and electronic properties of SrIn2As2. Superconductivity is observed in SrIn2As2 for pressure where the temperature dependence of the resistivity changes from a semiconducting-like behavior to that of a metal. The observation of nontrivial topological states and pressure-induced superconductivity in SrIn2As2 provides crucial insights into the relationship between topology and superconductivity, as well as stimulates further studies of superconductivity in topological materials.