Structural evolution and superconductivity of arsenic under high pressure

This study investigates the structural evolution and superconducting mechanisms of arsenic (As) under pressures ranging from 0 to 400 GPa using first-principles calculations. The phase transition sequence aligns with experimental data ( $R\overline{3}m$ - $Pm\overline{3}m$ -HG phase- $Im\overline{3}m$ ), with the As phase demonstrating stability between 100 and 400 GPa. At 100 GPa, the As-IV ( $Im\overline{3}m$ ) phase exhibits a superconducting transition temperature (T_c) of 5.5 K, driven by As-p orbital hybridization, which enhances the density of states at the Fermi level and strengthens electron-phonon coupling. However, as pressure increases, electronic structure changes suppress superconductivity, with a shift in the VHS peak and a decrease in p-orbital contributions, leading to a T_c drop near zero at 400 GPa. These results suggest a potential phase transition above 400 GPa and offer insights for future high-pressure studies of arsenic.

The electronic properties are calculated using density functional theory (DFT) implemented in the CASTEP code, employing the projector augmented-wave (PAW) method for the plane-wave expansion. The exchange-correlation interaction is described using the PBE functional within the generalized gradient approximation (GGA). Electron-phonon coupling (EPC) and superconducting properties are computed with the QUANTUM ESPRESSO code, utilizing the optimized norm-conserving Vanderbilt pseudopotential (ONCVPSP).