Achieving band convergence by tuning the bonding ionicity in n-type Mg 3 Sb 2

Xin Sun, Xin Li, Jiong Yang*, Jinyang Xi, Ryky Nelson, Christina Ertural, Richard Dronskowski, Weishu Liu, Gerald J. Snyder, David J. Singh, Wenqing Zhang

*Corresponding author for this work

Research output: Contribution to journalArticle

14 Scopus citations

Abstract

Identifying strategies for beneficial band engineering is crucial for the optimization of thermoelectric (TE) materials. In this study, we demonstrate the beneficial effects of ionic dopants on n-type Mg 3 Sb 2 . Using the band-resolved projected crystal orbital Hamilton population, the covalent characters of the bonding between Mg atoms at different sites are observed. By partially substituting the Mg at the octahedral sites with more ionic dopants, such as Ca and Yb, the conduction band minimum (CBM) of Mg 3 Sb 2 is altered to be more anisotropic with an enhanced band degeneracy of 7. The CBM density of states of doped Mg 3 Sb 2 with these dopants is significantly enlarged by band engineering. The improved Seebeck coefficients and power factors, together with the reduced lattice thermal conductivities, imply that the partial introduction of more ionic dopants in Mg 3 Sb 2 is a general solution for its n-type TE performance.

Original languageEnglish (US)
Pages (from-to)1693-1700
Number of pages8
JournalJournal of computational chemistry
Volume40
Issue number18
DOIs
StatePublished - Jul 5 2019

Keywords

  • Mg Sb
  • band engineering
  • band-resolved COHP
  • bonding ionicity
  • thermoelectric

ASJC Scopus subject areas

  • Chemistry(all)
  • Computational Mathematics

Fingerprint Dive into the research topics of 'Achieving band convergence by tuning the bonding ionicity in n-type Mg <sub>3</sub> Sb <sub>2</sub>'. Together they form a unique fingerprint.

Cite this