Structural Phase Transitions and the Equation of State in SnSe at High Pressures up to 2 Mbar

Resumo

The crystal structure of tin selenide SnSe has been studied under quasihydrostatic compression at pressures up to 205 GPa created in diamond anvil cells at room temperature. Two structural phase transitions have been detected at and P ≈ 2.5 32 GPa. The former phase transition is continuous from the GeS-type structure (space group Pbnm) to the TlI-type structure (space group Cmcm). The phase transition to the CsCl-type cubic structure (space group Pm\(\bar 3\)m) occurs at 32 GPa and is accompanied by a stepwise decrease in the volume of the unit cell by 7%. The pressure dependence of the specific volume of the unit cell at room temperature has been constructed up to 205 GPa.