High pressure structural and transport measurements of InTe, GaTe, and InGaTe2 Original Research Article

In this paper, the effect of pressure on the transport and structural properties of GaTe, InTe, and InGaTe2 is reported. All materials were found to exhibit pressure-induced structural transitions. For GaTe, the ambient structure transforms to a mixed state at 8 GPa, which transforms at 15 GPa to an ordered state. InTe, which crystallizes in a tetragonal structure, shows transformations at 6 and 14 GPa. InGaTe2, also initially tetragonal, undergoes two transitions at 9.25 GPa and 13 GPa. These transitions have shown noticeable effects on the transport properties. In particular, the Seebeck coefficient for the solid solution changes sign at the first phase transition. From these results, the thermoelectric figure of merit has been evaluated for each material. For some of these materials (InTe and InGaTe2) this yields a lower efficiency than ambient conditions. However, for GaTe, this has been shown to increase the figure of merit by 14 times to 8 GPa.