Thermoelectric power and phase transition of polycrystalline As ₂Te₃ under pressure

The pressure dependence of the thermoelectric power of monoclinic As ₂Te₃ is measured up to 10 GPa using a Mao-Bell diamond anvil cell. The thermoelectric power never reaches an absolute value greater than the ambient pressure value of 242 μV/K. Evidence of a phase transition is present between 6 and 8 GPa where the thermoelectric power reaches an absolute value of 225 μV/K after passing through a minimum of S≈75 μV/K. X-ray diffraction experiments confirm that the resulting structure is β-As₂Te₃, which is isostructural with Bi ₂Te₃ and Sb₂Te₃.