Effects of Cu doping on thermoelectric properties of Al–Si–Ru semiconducting quasicrystalline approximant

Yutaka Iwasaki, Koichi Kitahara, and Kaoru Kimura
Phys. Rev. Materials 5, 125401 – Published 3 December 2021
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Abstract

We have attempted to improve the thermoelectric performance of an Al–Si–Ru semiconducting approximant through optimizing the carrier concentration. The effects of Cu doping on the thermoelectric properties of an Al–Si–Ru semiconducting quasicrystalline approximant with the nominal composition of Al690.75xSi7.5CuxRu23.50.25x(x=0,2,4,6,8) are investigated. At approximately room temperature, an increase of x leads to a decrease of the Seebeck coefficient S and an increase of the electrical conductivity. Density functional theory and the Boltzmann transport theory are used to calculate S as the hole concentration and the band gap are varied. The temperature dependence of S is quantitatively described by an increase of the hole concentration and narrowing of the band gap with increasing x. Cu doping is shown to increase the hole concentration and narrow the band gap. The maximum dimensionless figure of merit increases from 0.03 at 400 K for x=0 to 0.2 at 500 K for x=4. These results indicate that the semiconducting quasicrystalline approximant could be a suitable candidate as a thermoelectric material for low grade waste heat recovery.

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  • Received 27 March 2021
  • Accepted 23 November 2021

DOI:https://doi.org/10.1103/PhysRevMaterials.5.125401

©2021 American Physical Society

Physics Subject Headings (PhySH)

Condensed Matter, Materials & Applied Physics

Authors & Affiliations

Yutaka Iwasaki1,*, Koichi Kitahara1,2, and Kaoru Kimura1,2

  • 1Department of Advanced Materials Science, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8561, Japan
  • 2AIST–UTokyo, Advanced Operando-Measurement Technology Open Innovation Laboratory (OPERANDO–OIL), National Institute of Advanced Industrial Science and Technology (AIST), 148 City Block 4, Kashiwanoha Campus, 178-4 Wakashiba, Kashiwa, Chiba 277-0871, Japan

  • *iwasaki@phys.mm.t.u-tokyo.ac.jp

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Issue

Vol. 5, Iss. 12 — December 2021

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