Dependency of a localized phonon mode intensity on compositional cluster size in SiGe alloys

Sylvia Yuk Yee Chung*, Motohiro Tomita, Junya Takizawa, Ryo Yokogawa, Atsushi Ogura, Haidong Wang, Takanobu Watanabe

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

Using molecular dynamics, we found that the localized phonon-mode spectrum in SiGe alloys, which was recently discovered by an inelastic x-ray scattering experiment, changes according to the size distribution of compositional clusters in alloys. By varying the spatial distributions of Si and Ge, alloy models with differing compositions of Si and Ge clusters were able to be produced. For a range of alloys comprising 20%-80% Ge, a mixture of small and intermediate sized clusters will give the highest intensities of the local mode. The Si-Ge optical mode intensity increases with the local mode intensity, but the Si-Ge bond alone is not sufficient to produce the local mode. Si rich alloys with small Ge clusters produce the highest local mode intensities, suggesting that this mode is caused by small Ge clusters surrounded by Si pairs.

Original languageEnglish
Article number075017
JournalAIP Advances
Volume11
Issue number7
DOIs
Publication statusPublished - 2021 Jul 1

ASJC Scopus subject areas

  • Physics and Astronomy(all)

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