Reinvestigation of thermoelectric properties of n- and p-type Ba 8-d Au x Si46-x-y clathrate

Shinji Munetoh, Makoto Saisho, Takuya Oka, Toshiko Osada, Hideshi Miura, Osamu Furukimi

Research output: Contribution to journalArticle

3 Citations (Scopus)

Abstract

We have synthesized n- and p-type clathrates Ba8-d Au x Si46-x-y with various Au contents (4.6 < x < 6.0) by arc-melting, annealing at 1173 K, and spark plasma sintering at 1073 K. The Au compositions found by wavelength-dispersive x-ray spectrometry for the synthesized samples were slightly lower than the nominal compositions. Ba 7.8Au4.6Si41.4 and Ba7.7Au 4.9Si41.1 samples showed n- and p-type conduction, respectively. According to the electron count (Ba2+) 8Au(3-)5.33Si40.67, the clathrate composition with x = 5.33 is expected to be an intrinsic semiconductor. Our experimental results show that increase of the Au composition causes a transition from n-type to p-type conduction between x = 4.6 and 4.9. We have also calculated the band structures of the Ba8Au x Si 46-x clathrate including a vacancy by ab initio calculation based on density functional theory with structure optimization. It was found that the vacancy behaves like an electron acceptor and the numbers of vacancies at 24k sites for the synthesized Ba8Au x Si46-x-y clathrates can be estimated as ∼0.4 in a unit cell.

Original languageEnglish
Pages (from-to)2430-2434
Number of pages5
JournalJournal of Electronic Materials
Volume43
Issue number6
DOIs
Publication statusPublished - Jan 1 2014

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All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Electrical and Electronic Engineering
  • Materials Chemistry

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