Author:
Shoker M. B.,Alhaddad T.,Pagès O.,Torres V. J. B.,Postnikov A. V.,Polian A.,Hajj Hussein R.,Pradhan G. K.,Narayana C.,Gardiennet C.,Kervern G.,Nataf L.,Ravy S.,Itié J.-P.,Strzałkowski K.,Marasek A.,Firszt F.
Abstract
AbstractRaman scattering and ab initio Raman/phonon calculations, supported by X-ray diffraction, are combined to study the vibrational properties of Zn1−xBexTe 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 doublet shifted in block under pressure. When a bond achieves lower content and merely self-connects via (finite/infinite) treelike chains, the coupling is undermined by overdamping of the in-chain stretching until a «phonon exceptional point» is reached at the resonance. Only the out-of-chain vibrations «survive» the resonance, the in-chain ones are «killed». This picture is not bond-related, and hence presumably generic to mixed crystals of the closing-type under pressure (dominant over the opening-type), indicating a key role of the mesostructure in the pressure dependence of phonons in mixed crystals.
Funder
Indo-French Centre for the Promotion of Advanced Research
Project i3n, financed through FCT/MCTES
Publisher
Springer Science and Business Media LLC
Reference40 articles.
1. Waag, A. et al. Novel beryllum containing II-VI compounds: Basic properties and potential applications. J. Cryst. Growth 184(185), 1–10 (1998).
2. Vérié, C. Beryllium substitution-mediated covalency engineering of II-VI alloys for lattice elastic rigidity reinforcement. J. Cryst. Growth 184(185), 1061–1066 (1998).
3. Christensen, N. E., Satpathy, S. & Pawlowska, Z. Bonding and ionicity in semiconductors. Phys. Rev. B 36, 1032–1050 (1987).
4. Taylor, D. W. Phonon response theory and the infrared and Raman experiments. In Optical properties of Mixed Crystals (eds Elliott, R. J. & Ipatova, I. P.) 35–131 (Elsevier, 1988).
5. Adachi, S. Lattice dynamics properties. In Properties of Semiconductor Alloys: Group-IV, III-V and II-VI (ed. Adachi, S.) 99–124 (Wiley, 2009).
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