Structural evolution and superconductivity of arsenic under high pressure

Area of Science:

• Condensed Matter Physics
• Materials Science
• Computational Chemistry

Background:

• Arsenic (As) exhibits complex structural and electronic properties under extreme pressure.
• Understanding high-pressure phases is crucial for discovering novel superconducting materials.

Purpose of the Study:

• To investigate the structural evolution of arsenic under high pressure (0-400 GPa).
• To elucidate the superconducting mechanisms in high-pressure arsenic phases.
• To predict potential new phases and superconducting behaviors.

Main Methods:

• First-principles calculations were employed to study structural and electronic properties.
• Density Functional Theory (DFT) with the PBE functional (GGA) was used.
• Electron-phonon coupling (EPC) and superconducting properties were calculated using QUANTUM ESPRESSO.

Main Results:

• The study identified a phase transition sequence matching experimental data: R-3m to Pm-3m to Im-3m.
• The As-IV (Im-3m) phase is stable between 100-400 GPa, exhibiting superconductivity with a T_c of 5.5 K at 100 GPa.
• Superconductivity is driven by As-p orbital hybridization, but suppressed by electronic structure changes at higher pressures, leading to near-zero T_c at 400 GPa.

Conclusions:

• Arsenic exhibits pressure-induced superconductivity, with T_c peaking at 100 GPa.
• Electronic structure modifications under increasing pressure lead to a suppression of superconductivity.
• A potential phase transition above 400 GPa is suggested, warranting further investigation.