Pressure-induced structural and superconducting transitions in black arsenic

TL;DR

This study investigates how black arsenic's structure and superconductivity change under high pressure, revealing phase transitions and the emergence of superconductivity with increasing pressure up to 58 GPa.

Contribution

It provides detailed high-pressure Raman, resistance, and theoretical data on black arsenic's phase transitions and superconductivity, updating existing phase diagrams.

Findings

Metastable black arsenic transforms to gray arsenic at 1.51 GPa.

Superconductivity appears above 25 GPa with Tc around 3 K.

Tc increases to about 4.5 K in the incommensurate phase above 43 GPa.

Abstract

We report high-pressure Raman spectra and resistance measurements of black arsenic (b-As) up to 58 GPa, along with phonon density of states (DOS) and enthalpy calculations for four reported arsenic phases up to 50 GPa. It is found that metastable b-As transforms into gray arsenic (g-As) phase at a critical pressure of 1.51 GPa, followed by subsequent transitions to simple cubic arsenic (c-As) and incommensurate host-guest arsenic (hg-As) phases at 25.9 and 44.8 GPa, respectively. Superconductivity emerges above 25 GPa in the c-As phase, with the superconducting transition temperature ($T$$\rm_c$) remaining nearly a constant of 3 K. Upon further compression, $T$$\rm_c$ steeply increases to a higher value around 4.5 K in the incommensurate hg-As phase above 43 GPa. We use our results to update the structural and superconducting phase diagrams under pressure for the novel semiconductor, black arsenic.