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Article: High-performance GeTe thermoelectrics in both rhombohedral and cubic phases

TitleHigh-performance GeTe thermoelectrics in both rhombohedral and cubic phases
Authors
Keywordscontrolled study
crystal structure
phase transition
phonon
solubility
Issue Date2018
PublisherAmerican Chemical Society. The Journal's web site is located at http://pubs.acs.org/journals/jacsat/index.html
Citation
Journal of the American Chemical Society, 2018, v. 140 n. 47, p. 16190-16197 How to Cite?
AbstractGeTe experiences phase transition between cubic and rhombohedral through distortion along the [111] direction. Cubic GeTe shares the similarity of a two-valence-band structure (high-energy L and low-energy Σ bands) with other cubic IV–VI semiconductors such as PbTe, SnTe, and PbSe, and all show a high thermoelectric performance due to a high band degeneracy. Very recently, the two valence bands were found to switch in energy in rhombohedral GeTe and to be split due to symmetry-breaking of the crystal structure. This enables the overall band degeneracy to be manipulated either by the control of symmetry-induced degeneracy or by the design of energy-aligned orbital degeneracy. Here, we show Sb-doping for optimizing carrier concentration and manipulating the degree of rhombohedral lattice distortion to maximize the band degeneracy and then electronic performance. In addition, Sb-doping significantly promotes the solubility of PbTe, enhancing the scattering of phonons by Ge/Pb substitutional defects for minimizing the lattice thermal conductivity. This successfully realizes a superior thermoelectric figure of merit, zT of >2 in both rhombohedral and cubic GeTe, demonstrating these alloys as top candidates for thermoelectric applications at T < 800 K. This work further sheds light on the importance of crystal structure symmetry manipulation for advancing thermoelectrics.
Persistent Identifierhttp://hdl.handle.net/10722/272238
ISSN
2023 Impact Factor: 14.4
2023 SCImago Journal Rankings: 5.489
ISI Accession Number ID
Grants

 

DC FieldValueLanguage
dc.contributor.authorLi, J-
dc.contributor.authorZhang, X-
dc.contributor.authorWang, X-
dc.contributor.authorBu, Z-
dc.contributor.authorZheng, L-
dc.contributor.authorZhou, B-
dc.contributor.authorXIONG, F-
dc.contributor.authorChen, Y-
dc.contributor.authorPei, Y-
dc.date.accessioned2019-07-20T10:38:23Z-
dc.date.available2019-07-20T10:38:23Z-
dc.date.issued2018-
dc.identifier.citationJournal of the American Chemical Society, 2018, v. 140 n. 47, p. 16190-16197-
dc.identifier.issn0002-7863-
dc.identifier.urihttp://hdl.handle.net/10722/272238-
dc.description.abstractGeTe experiences phase transition between cubic and rhombohedral through distortion along the [111] direction. Cubic GeTe shares the similarity of a two-valence-band structure (high-energy L and low-energy Σ bands) with other cubic IV–VI semiconductors such as PbTe, SnTe, and PbSe, and all show a high thermoelectric performance due to a high band degeneracy. Very recently, the two valence bands were found to switch in energy in rhombohedral GeTe and to be split due to symmetry-breaking of the crystal structure. This enables the overall band degeneracy to be manipulated either by the control of symmetry-induced degeneracy or by the design of energy-aligned orbital degeneracy. Here, we show Sb-doping for optimizing carrier concentration and manipulating the degree of rhombohedral lattice distortion to maximize the band degeneracy and then electronic performance. In addition, Sb-doping significantly promotes the solubility of PbTe, enhancing the scattering of phonons by Ge/Pb substitutional defects for minimizing the lattice thermal conductivity. This successfully realizes a superior thermoelectric figure of merit, zT of >2 in both rhombohedral and cubic GeTe, demonstrating these alloys as top candidates for thermoelectric applications at T < 800 K. This work further sheds light on the importance of crystal structure symmetry manipulation for advancing thermoelectrics.-
dc.languageeng-
dc.publisherAmerican Chemical Society. The Journal's web site is located at http://pubs.acs.org/journals/jacsat/index.html-
dc.relation.ispartofJournal of the American Chemical Society-
dc.rightsThis document is the Accepted Manuscript version of a Published Work that appeared in final form in [JournalTitle], copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see [insert ACS Articles on Request author-directed link to Published Work, see http://pubs.acs.org/page/policy/articlesonrequest/index.html].-
dc.subjectcontrolled study-
dc.subjectcrystal structure-
dc.subjectphase transition-
dc.subjectphonon-
dc.subjectsolubility-
dc.titleHigh-performance GeTe thermoelectrics in both rhombohedral and cubic phases-
dc.typeArticle-
dc.identifier.emailChen, Y: yuechen@hku.hk-
dc.identifier.authorityChen, Y=rp01925-
dc.description.naturelink_to_subscribed_fulltext-
dc.identifier.doi10.1021/jacs.8b09147-
dc.identifier.pmid30360620-
dc.identifier.scopuseid_2-s2.0-85057250617-
dc.identifier.hkuros298966-
dc.identifier.volume140-
dc.identifier.issue47-
dc.identifier.spage16190-
dc.identifier.epage16197-
dc.identifier.isiWOS:000451933100029-
dc.publisher.placeUnited States-
dc.relation.projectA combined theoretical and experimental study of the vibrational and thermal-transport properties of partially liquid-like crystalline solids-
dc.identifier.issnl0002-7863-

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