The importance of the Mg-Mg interaction in Mg3Sb2-Mg3Bi2 shown through cation site alloying

Max Wood, Kazuki Imasato, Shashwat Anand, Jiong Yang, G. Jeffrey Snyder*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

7 Scopus citations

Abstract

Herein we study the effect alloying Yb onto the octahedral cite of Te doped Mg3Sb1.5Bi0.5 has on transport and the material's high temperature stability. We show that the reduction in mobility can be well explained with an alloy scattering argument due to disrupting the Mgoctahedral-Mgtetrahedral interaction that is important for placing the conduction band minimum at a location with high valley degeneracy. We note this interaction likely dominates the conducting states across n-type Mg3Sb2-Mg3Bi2 solid solutions and explains why alloying on the anion site with Bi isn't detrimental to Mg3Sb2's mobility. In addition to disrupting this Mg-Mg interaction, we find that alloying Yb into the Mg3Sb2 structure reduces its n-type dopability, likely originating from a change in the octahedral site's vacancy formation energy. We conclude showing that while the material's figure of merit is reduced with the addition of Yb alloying, its high temperature stability is greatly improved. This study demonstrates a site-specific alloying effect that will be important in other complex thermoelectric semiconductors such as Zintl phases.

Original languageEnglish (US)
Pages (from-to)2033-2038
Number of pages6
JournalJournal of Materials Chemistry A
Volume8
Issue number4
DOIs
StatePublished - 2020

ASJC Scopus subject areas

  • Chemistry(all)
  • Renewable Energy, Sustainability and the Environment
  • Materials Science(all)

Fingerprint Dive into the research topics of 'The importance of the Mg-Mg interaction in Mg<sub>3</sub>Sb<sub>2</sub>-Mg<sub>3</sub>Bi<sub>2</sub> shown through cation site alloying'. Together they form a unique fingerprint.

Cite this