Structural and electric transport properties of gray arsenic under high pressure

Gray arsenic is a two-dimensional semimetal material that has attracted much attention due to its rich and fascinating properties such as ultrahigh carrier mobility and giant magnetoresistance properties. In this work, the structural and electrical properties of gray arsenic under high pressure have been systematically explored. Two structural phase transitions, A7 phase of gray arsenic to simple cubic phase and simple cubic phase to host-guest phase, were revealed at ∼28 and ∼35 GPa, respectively. And the transition to host-guest phase completed at ∼46 GPa. Superconductivity appeared after ∼35 GPa and the maximum of $T_c$, ∼5 K, was revealed in pure host-guest phase at ∼54 GPa, which is currently the highest recorded $T_c$ of arsenic. The anisotropic upper critical field of superconductivities revealed the presence of mixed phase and the relative crystal orientations of the high-pressure phases.