Pressure-induced metallization and superconducting phase in ReS2

TL;DR

This study investigates how high pressure induces structural changes, metallization, and superconductivity in ReS2, combining theoretical predictions with experimental validation to reveal pressure-driven phase transitions and superconducting behavior.

Contribution

The paper predicts new high-pressure phases of ReS2 and demonstrates pressure-induced metallization and superconductivity through combined theoretical and experimental approaches.

Findings

ReS2 transitions from semiconductor to metal at ~70 GPa

A superconducting phase emerges at high pressure with Tc around 2 K

Experimental results confirm theoretical predictions of phase transitions

Abstract

Among the family of TMDs, ReS2 takes a special position, which crystalizes in a unique distorted low-symmetry structure at ambient conditions. The interlayer interaction in ReS2 is rather weak, thus its bulk properties are similar to that of monolayer. However, how does compression change its structure and electronic properties is unknown so far. Here using ab initio crystal structure searching techniques, we explore the high-pressure phase transitions of ReS2 extensively and predict two new high-pressure phases. The ambient pressure phase transforms to a "distorted-1T" structure at very low pressure and then to a tetragonal I41/amd structure at around 90 GPa. The "distorted-1T" structure undergoes a semiconductor-metal transition (SMT) at around 70 GPa with a band overlap mechanism. Electron-phonon calculations suggest that the I41/amd structure is superconducting and has a critical superconducting temperature of about 2 K at 100 GPa. We further perform high-pressure electrical resistance measurements up to 102 GPa. Our experiments confirm the SMT and the superconducting phase transition of ReS2 under high pressure. These experimental results are in good agreement with our theoretical predictions.