First-principles study of Si34-xGex clathrates: Direct wide-gap semiconductors in Si-Ge alloys

K. Moriguchi, S. Munetoh, A. Shintani

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116 Citations (Scopus)


Energetics and electronic states of Si34-xGex clathrate alloys have been investigated. The atomistic structures, the equations of state, and the lineup of band structures for these clathrates are calculated using the Vanderbilt ultra-soft pseudopotential method within the local-density-functional formalism. Some of these Si34-xGex clathrate alloys with an ideal Fd3̄m symmetry are found to have direct band gap at the π/a(111) (L) point in the Brillouin zone. The entire band gap of the Si34-xGex alloys is predicted to range between 1.2 and 2.0 eV. The total-energy difference between these clathrate alloys and the well-known sp3 Si-Ge alloys is less than 0.08 eV/atom. A method to synthesize these clathrate systems is also discussed. These Si-Ge clathrate alloys may find applications in optoelectronics semiconductor devices based on the Group-IV elements.

Original languageEnglish
Pages (from-to)7138-7143
Number of pages6
JournalPhysical Review B - Condensed Matter and Materials Physics
Issue number11
Publication statusPublished - Sept 15 2000
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics


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