While SnSe has been known as a high figure of merit (ZT) thermoelectric material at high temperatures, it has a low ZT at room temperature. SnSe has the β (Cmcm) phase at high temperature but the α (Pnma) phase at room temperature. In the present work, we first investigate the phase-transition temperature Tc between the α and β phases of SnSe based on density functional theory calculations and obtain 740 K, which is close to the experimental value of about 800 K. We then consider Ca alloying in SnSe and calculate Tc between the α and β phases of CaxSn1-xSe. It is found that the Ca alloying lowers Tc down to 220 K as the Ca content x increases up to x = 0.1875. For x > 0.14, CaxSn1-xSe is obtained to have the β phase at room temperature, allowing it to be suggested as a room-temperature high figure of merit thermoelectric material.
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© 2022 American Chemical Society
All Science Journal Classification (ASJC) codes
- Chemical Engineering (miscellaneous)
- Energy Engineering and Power Technology
- Materials Chemistry
- Electrical and Electronic Engineering