New stoichiometric compounds of Au-Hg system under high pressure.

ABSTRACT

We have extensively explored Au-Hg system under high pressure in the range of 0-300 GPa with and without spin-orbit coupling (SOC) inclusion. The variable-composition methodology has been used as employed in Universal Structure Predictor Evolutionary Xtallograpgy (USPEX) in combination with Vienna Ab initio Simulation Package (VASP). We have predicted several thermodynamically stable stoichiometric compounds of Au-Hg system, i.e. Au3Hg (space group 194, P63/mmc), AuHg (space group 62, Pnma), AuHg2 (space group 15, C2/c), AuHg9 (space group 38, Amm2) at 50 GPa; AuHg3 (space group 44, Imm2) at 100 GPa; Au3Hg2 (space group 15, C2/c) at 200 GPa and AuHg4 (space group 15, C2/c) at 300 GPa. We also found a phase transition of AuHg3 from Imm2 to P63/mmc at 248.5 GPa and 246.5 GPa with and without SOC, respectively.