Thermally induced band gap increase and high thermoelectric figure of merit of n-type PbTe

Unlike in many other semiconductors, the band gap of PbTe increases considerably with temperature. We compute the thermoelectric transport properties of n-type PbTe from first principles including the temperature variation of the electronic band structure. The calculated temperature dependence of th...

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Bibliographic Details
Published in:arXiv.org 2019-06
Main Authors: Cao, Jiang, Querales-Flores, José D, Fahy, Stephen, Savić, Ivana
Format: Article
Language:English
Subjects:
Band structure of solids
Energy gap
Figure of merit
First principles
Intermetallic compounds
Mathematical analysis
Semiconductors
Temperature
Temperature dependence
Thermoelectricity
Transport properties
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Summary:Unlike in many other semiconductors, the band gap of PbTe increases considerably with temperature. We compute the thermoelectric transport properties of n-type PbTe from first principles including the temperature variation of the electronic band structure. The calculated temperature dependence of the thermoelectric quantities of PbTe is in good agreement with previous experiments when the temperature changes of the band structure are accounted for. We also calculate the optimum band gap values which would maximize the thermoelectric figure of merit of n-type PbTe at various temperatures. We show that the actual gap values in PbTe closely follow the optimum ones between 300 K and 900 K, resulting in the high figure of merit. Our results indicate that an appreciable increase of the band gap with temperature in direct narrow-gap semiconductors is very beneficial for achieving high thermoelectric performance.
ISSN:2331-8422
DOI:10.48550/arxiv.1906.05322