Hole-doping effect on the thermoelectric properties and electronic structure of CoSi

C. S. Lue, Y. K. Kuo, C. L. Huang, W. J. Lai

Research output: Contribution to journalArticle

60 Citations (Scopus)

Abstract

We report the effect of Al substitution on the temperature-dependent electrical resistivity, Seebeck coefficient, as well as thermal conductivity in the binary compound cobalt monosilicide. It is found that the substitution of Al onto the Si sites causes a dramatic decrease in the electrical resistivity and lattice thermal conductivity. A theoretical analysis indicated that the reduction of lattice thermal conductivity arises mainly from point-defect scattering of the phonons. For x > ⨯ 0.05 in the CoSi1−x Alx system, the Seebeck coefficient changes sign from negative to positive, accompanied by the appearance of a broad maximum. These features are associated with the change in the electronic band structure, where the Fermi level shifts downwards from the center of the pseudogap due to hole-doping effect. While the thermoelectric performance improves with increasing Al substitution, the largest figure-of-merit ZT value among these alloys is still an order of magnitude lower than the conventional thermoelectric materials.

Original languageEnglish
JournalPhysical Review B - Condensed Matter and Materials Physics
Volume69
Issue number12
DOIs
Publication statusPublished - 2004 Mar 23

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

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