Abstract
is a promising thermoelectric alloy that exhibits a temperature dependent band inversion below 300 K. Recent work has shown that this band inversion also coincides with a trivial to nontrivial topological phase transition. To understand how the properties critical to thermoelectric efficiency are affected by the band inversion, we measured the broadband optical response of as a function of temperature. We find clear optical signatures suggesting the band inversion occurs at K, and use the extended Drude model to accurately determine a dependence of the bulk carrier lifetime, associated with electron-acoustic phonon scattering. Due to the high bulk carrier doping level, no discriminating signatures of the topological surface states are found, although their presence cannot be excluded from our data.
- Received 29 July 2014
- Revised 11 October 2014
DOI:https://doi.org/10.1103/PhysRevB.90.235144
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