Rhombohedral to Cubic Conversion of GeTe via MnTe Alloying Leads to Ultralow Thermal Conductivity, Electronic Band Convergence, and High Thermoelectric Performance.
In this study, a series of GeMnTe (x = 0-0.21) compounds were prepared by a melting-quenching-annealing process combined with spark plasma sintering (SPS). The effect of alloying MnTe into GeTe on the structure and thermoelectric properties of GeMnTe is profound. With increasing content of MnTe, the...
| Publicado en: | Journal of the American Chemical Society Vol. 140; no. 7; pp. 2673 - 2687 |
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| Autores principales: | , , , , , , , , , , , |
| Formato: | Artículo |
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American Chemical Society
2/21/2018
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| Materias: | |
| Acceso en línea: | Ver este registro en EBSCOhost |
| fields | @attributes: recordID: 1 pdfLink: plink: https://search.ebscohost.com/login.aspx?direct=true&db=hlh&AN=128201148&site=ehost-live header: @attributes: shortDbName: hlh uiTerm: 128201148 longDbName: Humanities International Complete uiTag: AN controlInfo: bkinfo: jinfo: jid: 00027863 ACS jtl: Journal of the American Chemical Society issn: 00027863 maglogo: N pubinfo: dt: 2/21/2018 vid: 140 iid: 7 pid: 997 pub: American Chemical Society artinfo: ui: 128201148 10.1021/jacs.7b13611 ppf: 2673 ppct: 14 formats: tig: atl: Rhombohedral to Cubic Conversion of GeTe via MnTe Alloying Leads to Ultralow Thermal Conductivity, Electronic Band Convergence, and High Thermoelectric Performance. aug: au: Zheng Zheng Rigui Deng Hongyao Xie Wei Liu Yonggao Yan Xinfeng Tang Xianli Su Stoumpos, Constantinos Kanatzidis, Mercouri G. Shiqiang Hao Wolverton, Chris Uher, Ctirad affil: State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan 430070, China Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, United States Department of Physics, University of Michigan, Ann Arbor, Michigan 48109, United States su: Thermal conductivity Thermoelectric materials Annealing of metals Density functional theory Hematite sug: subj: Thermal conductivity Thermoelectric materials Annealing of metals Density functional theory Hematite ab: In this study, a series of GeMnTe (x = 0-0.21) compounds were prepared by a melting-quenching-annealing process combined with spark plasma sintering (SPS). The effect of alloying MnTe into GeTe on the structure and thermoelectric properties of GeMnTe is profound. With increasing content of MnTe, the structure of the GeMnTe compounds gradually changes from rhombohedral to cubic, and the known R3m to Fm-3m phase transition temperature of GeTe moves from 700 K closer to room temperature. First-principles density functional theory calculations show that alloying MnTe into GeTe decreases the energy difference between the light and heavy valence bands in both the R3m and Fm-3m structures, enhancing a multiband character of the valence band edge that increases the hole carrier effective mass. The effect of this band convergence is a significant enhancement in the carrier effective mass from 1.44 m (GeTe) to 6.15 m (GeMnTe). In addition, alloying with MnTe decreases the phonon relaxation time by enhancing alloy scattering, reduces the phonon velocity, and increases Ge vacancies all of which result in an ultralow lattice thermal conductivity of 0.13 W m K at 823 K. Subsequent doping of the GeMnTe compositions with Sb lowers the typical very high hole carrier concentration and brings it closer to its optimal value enhancing the power factor, which combined with the ultralow thermal conductivity yields a maximum ZT value of 1.61 at 823 K (for GeMnSbTe). The average ZT value of the compound over the temperature range 400-800 K is 1.09, making it the best GeTe-based thermoelectric material. pubtype: Academic Journal doctype: Article src: R language: English refInfo: copyright: @attributes: flag: Y dt: @attributes: year: 2018 holdings: @attributes: islocal: N |
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