Exceptional phonon point versus free phonon coupling in Zn_1-xBe_xTe under pressure: an experimental and ab initio Raman study.

ABSTRACT: Raman scattering and ab initio Raman/phonon calculations, supported by X-ray diffraction, are combined to study the vibrational properties of Zn_1-xBe_xTe under pressure. The dependence of the Be-Te (distinct) and Zn-Te (compact) Raman doublets that distinguish between Be- and Zn-like environments is examined within the percolation model with special attention to x ~ (0,1). The Be-like environment hardens faster than the Zn-like one under pressure, resulting in the two sub-modes per doublet getting closer and mechanically coupled. When a bond is so dominant that it forms a matrix-like continuum, its two submodes freely couple on crossing at the resonance, with an effective transfer of oscillator strength. Post resonance the two submodes stabilize into an inverted double

SUBMITTER: Shoker MB 

PROVIDER: S-EPMC8760325 | biostudies-literature | 2022 Jan

REPOSITORIES: biostudies-literature