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Hybrid-Functional and Quasi-Particle Calculations of Band Structures of Mg2Si, Mg2Ge, and Mg2Sn

Ryu, Byungki and Park, Sungjin and Choi, Eun-Ae and de Boor, Johannes and Ziolkowski, Pawel and Chung, Jaywan and Park, Su Dong (2019) Hybrid-Functional and Quasi-Particle Calculations of Band Structures of Mg2Si, Mg2Ge, and Mg2Sn. Journal of the Korean Physical Society. Springer. DOI: 10.3938/jkps.75.144 ISSN 0374-4884

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Abstract

We perform hybrid functional and quasi-particle band structure calculations with spin-orbit interaction to investigate the band structures of Mg2Si, Mg2Ge, and Mg2Sn. For all Mg2X materials, where X = Si, Ge, and Sn, the characteristics of band edge states, i.e., band and valley degeneracies, and orbital characters, are found to be conserved, independent of the computational schemes such as density functional generalized gradient approximation, hybrid functionals, or quasi-particle calculations. However, the magnitude of the calculated band gap varies significantly with the computational schemes. Within density-functional calculations, the one-particle band gaps of Mg2Si, Mg2Ge, and Mg2Sn are 0.191, 0.090, and −0.346 eV, respectively, and thus severely underestimated compared to the experimental gaps, due to the band gap error in the density functional theory and the significant relativistic effect on the low-energy band structures. By employing hybrid-functional calculations with a 35% fraction of the exact Hartree-Fock exchange energy (HSE-35%), we overcame the negative band gap issue in Mg2Sn. Finally, in quasi-particle calculations on top of the HSE-35% Hamiltonians, we obtained band gaps of 0.835, 0.759, and 0.244 eV for Mg2Si, Mg2Ge, and Mg2Sn, respectively, consistent with the experimental band gaps of 0.77, 0.74, and 0.36 eV, respectively.

Item URL in elib:https://elib.dlr.de/130591/
Document Type:Article
Title:Hybrid-Functional and Quasi-Particle Calculations of Band Structures of Mg2Si, Mg2Ge, and Mg2Sn
Authors:
AuthorsInstitution or Email of AuthorsAuthors ORCID iD
Ryu, ByungkiEnergy Conversion Research Center, Electrical Materials Research Division, Korea Electrotechnology Research Institute (KERI), Changwon, KoreaUNSPECIFIED
Park, SungjinEnergy Conversion Research Center, Electrical Materials Research Division, Korea Electrotechnology Research Institute (KERI), Changwon, KoreaUNSPECIFIED
Choi, Eun-AeComputational Materials Department, Materials Processing Innovation Research Division, Korea Institute of Materials Science (KIMS), Changwon, KoreaUNSPECIFIED
de Boor, JohannesGerman aerospace center, institute of materials research, köln, germanyhttps://orcid.org/0000-0002-1868-3167
Ziolkowski, PawelGerman Aerospace Center, Institute of Materials Research, Köln, GermanyUNSPECIFIED
Chung, JaywanEnergy Conversion Research Center, Electrical Materials Research Division, Korea Electrotechnology Research Institute (KERI), Changwon, KoreaUNSPECIFIED
Park, Su DongEnergy Conversion Research Center, Electrical Materials Research Division, Korea Electrotechnology Research Institute (KERI), Changwon, KoreaUNSPECIFIED
Date:22 July 2019
Journal or Publication Title:Journal of the Korean Physical Society
Refereed publication:Yes
Open Access:No
Gold Open Access:No
In SCOPUS:Yes
In ISI Web of Science:Yes
DOI :10.3938/jkps.75.144
Publisher:Springer
ISSN:0374-4884
Status:Published
Keywords:Thermoelectric; band gap; GW calculation; Mg2Si; Band convergence
HGF - Research field:Aeronautics, Space and Transport
HGF - Program:Space
HGF - Program Themes:Space Technology
DLR - Research area:Raumfahrt
DLR - Program:R SY - Technik für Raumfahrtsysteme
DLR - Research theme (Project):R - Systemtechnologien
Location: Köln-Porz
Institutes and Institutions:Institute of Materials Research > Thermoelectric Materials and Systems
Deposited By: Yasseri, Mohammad
Deposited On:15 Nov 2019 15:19
Last Modified:15 Nov 2019 15:19

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