Multi-phonon (percolation) behavior and local clustering of CdxZn1−xSe-cubic mixed crystals (x ≤ 0.3): A Raman–ab initio study

Autor: Alain Maillard, Jean-Paul Itié, Mala N. Rao, Olivier Pagès, Andrei Postnikov, Alain Polian, Franciszek Firszt, A. En Naciri, Vitor J.B. Torres, H. Dicko, M. B. Shoker, Rekha Rao, Laurent Broch, Karol Strzałkowski
Přispěvatelé: Laboratoire de Chimie et Physique - Approche Multi-échelle des Milieux Complexes (LCP-A2MC), Université de Lorraine (UL), Institut de minéralogie et de physique des milieux condensés (IMPMC), Université Pierre et Marie Curie - Paris 6 (UPMC)-IPG PARIS-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Institute of Physics [Toruń], Faculty of Physics, Astronomy and Informatics [Toruń], Nicolaus Copernicus University [Toruń]-Nicolaus Copernicus University [Toruń], Bhabha Atomic Research Center, Mumbai, India, Bhabha Atomic Research Center (BARC), Government of India, Department of Atomic Energy, Laboratoire Matériaux Optiques, Photonique et Systèmes (LMOPS), CentraleSupélec-Université de Lorraine (UL), Synchrotron SOLEIL (SSOLEIL), Centre National de la Recherche Scientifique (CNRS), Universidade de Aveiro, Institut de minéralogie, de physique des matériaux et de cosmochimie (IMPMC), Muséum national d'Histoire naturelle (MNHN)-Institut de recherche pour le développement [IRD] : UR206-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Bhabha Atomic Research Centre (BARC), Université de Lorraine (UL)-CentraleSupélec
Jazyk: angličtina
Rok vydání: 2019
Předmět:
Zdroj: Journal of Applied Physics
Journal of Applied Physics, American Institute of Physics, 2019, 126 (10), pp.105707. ⟨10.1063/1.5111106⟩
Journal of Applied Physics, 2019, 126 (10), pp.105707. ⟨10.1063/1.5111106⟩
ISSN: 0021-8979
1089-7550
Popis: International audience; We present a polarization-dependent pure transverse-optic (TO) Raman study of high-quality Cd x Zn 1−x Se single crystals with zincblende (cubic) structures (x 0:3) covering both the phonon and phonon-polariton variants of the TO modes, using suitable backward and near-forward scattering geometries, respectively. Insight into the native phonon regime of the phonon-polaritons is obtained at intermediate composition of the random crystal (x ¼ 0:5, 0:3) and at the (Cd,Zn)-dilute limits (x 0:1; using prototype impurity motifs) by applying ab initio codes to large supercells (64-216 atoms), with special attention to both the Raman intensities and the phonon frequencies. The experimental (Raman) and theoretical (ab initio) results converge onto a percolation-type three-phonon [1 Â (Cd-Se), 2 Â (Zn-Se)] pattern for Cd x Zn 1−x Se. On the practical side, the interplay between the oscillator strengths of the two Zn-Se Raman modes is used to diagnose a pronounced trend toward local clustering in the studied crystals, presumably an early sign of the composition-induced zincblende ⇿ wurtzite structural transition (x 0:3). The deviation from the ideal Zn ⇿ Cd random substitution is estimated by working out a zincblende-version of the percolation model equipped with a relevant order parameter κ. The model is based on a sensitivity of the Zn-Se vibration to its local environment at the second-neighbor scale, independently supported by ab initio calculation of the Raman spectra in their dependence on κ (adjusted by simulated annealing)
Databáze: OpenAIRE
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