Tuning valley degeneracy with band inversion
Journal Article
·
· Journal of Materials Chemistry. A
- Northwestern Univ., Evanston, IL (United States); OSTI
- Northwestern Univ., Evanston, IL (United States)
- Univ. of Illinois at Urbana-Champaign, IL (United States)
- University of Notre Dame, IN (United States)
Valley degeneracy is a key feature of the electronic structure that benefits the thermoelectric performance of a material. Despite recent studies which claim that high valley degeneracy can be achieved with inverted bands, our analysis of rock-salt IV–VI compounds using first-principles calculations and k•p perturbation theory demonstrates that mere band inversion is an insufficient condition for high valley degeneracy; rather, there is a critical degree to which the bands must be inverted to induce multiple carrier pockets. The so-called “band inversion parameter” is formalized as a chemically-tunable property, offering a design route to achieving high valley degeneracy in compounds with inverted bands. In conclusion, we predict that the valley degeneracy of rock-salt IV–VI compounds can be increased from NV = 4 to NV = 24, which could result in a corresponding increase in the thermoelectric figure of merit zT.
- Research Organization:
- Krell Institute, Ames, IA (United States)
- Sponsoring Organization:
- National Science Foundation (NSF); USDOE; USDOE Office of Science (SC)
- Grant/Contract Number:
- SC0020347
- OSTI ID:
- 1978844
- Alternate ID(s):
- OSTI ID: 1838396
- Journal Information:
- Journal of Materials Chemistry. A, Journal Name: Journal of Materials Chemistry. A Journal Issue: 3 Vol. 10; ISSN 2050-7488
- Publisher:
- Royal Society of ChemistryCopyright Statement
- Country of Publication:
- United States
- Language:
- English
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