Superconductivity in multiple phases of compressed GeSb2Te4

TL;DR

This study reports the discovery of superconductivity in different phases of compressed GeSb2Te4, revealing pressure-dependent critical temperatures and a superconductor-insulator transition, advancing understanding of phase change memory alloys.

Contribution

It demonstrates superconductivity in both amorphous and crystalline phases of GeSb2Te4 under pressure, showing continuous control of electronic properties and a superconductor-insulator transition.

Findings

Superconductivity observed in amorphous and crystalline phases.

Critical temperature increases with pressure, reaching 6K and 8K.

Pressure enables continuous control of electronic properties.

Abstract

Here we report the discovery of superconductivity in multiple phases of the compressed GeSb2Te4 (GST) phase change memory alloy, which has attracted considerable attention for the last decade due to its unusual physical properties with many potential applications. Superconductivity is observed through electrical transport measurements, both for the amorphous (a-GST) and for the crystalline (c-GST) phases. The superconducting critical temperature, TC, continuously increases with the applied pressure reaching a maximum Tc =6K at P=20 GPa for a-GST, whereas the critical temperature of the cubic phase reaches a maximum Tc =8 K at 30 GPa. This new material system, exhibiting a superconductor-insulator quantum phase transition (SIT) has an advantage over disordered metals since it has a continuous control of the crystal structure and the electronic properties using pressure as an external stimulus, which was lacking in SIT studies until today.