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

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. AuHg (space group 194, P63/mmc), AuHg (space group 62, Pnma), AuHg (space group 15, C2/c), AuHg (space group 38, Amm2) at 50 GPa; AuHg (space group 44, Imm2) at 100 GPa; AuHg (space group 15, C2/c) at 200 GPa and AuHg (space group 15, C2/c) at 300 GPa. We also found a phase transition of AuHg from Imm2 to P63/mmc at 248.5 GPa and 246.5 GPa with and without SOC, respectively.