# Pressure-Induced Exciton Formation and Superconductivity in Platinum-Based Mineral Sperrylite

## TL;DR

This study explores how pressure affects the electronic properties of Sperrylite, revealing superconductivity and exciton formation at high pressures.

## Contribution

The paper identifies pressure-induced excitonic states and superconductivity in Sperrylite, offering new insights into high-pressure material behavior.

## Key findings

- Sperrylite becomes superconducting at pressures above 92 GPa with a resistance drop near 3 K.
- Electronic band structure calculations show a non-monotonic evolution consistent with exciton formation.
- A Lifshitz transition and increased density of states explain the onset of superconductivity.

## Abstract

We report a comprehensive study of Sperrylite (PtAs2), the main platinum source in natural minerals, as a function of applied pressures up to 150 GPa. While no structural phase transition is detected from pressure-dependent X-ray measurements, the unit cell volume shrinks monotonically with pressure following the third-order Birch–Murnaghan equation of state. The mildly semiconducting behavior found in pure synthesized crystals at ambient pressures becomes more insulating upon increasing the applied pressure before metalizing at higher pressures, giving way to the appearance of an abrupt decrease in resistance near 3 K at pressures above 92 GPa consistent with the onset of a superconducing phase. The pressure evolution of the calculated electronic band structure reveals the same physical trend as our transport measurements, with a non-monotonic evolution explained by a hole band that is pushed below the Fermi energy and an electron band that approaches it as a function of pressure, both reaching a touching point suggestive of an excitonic state. A Lifshitz transition of the electronic structure and an increase in the density of states may naturally explain the onset of superconductivity in this material.