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- Title
Vibrational-mechanical properties of the highly-mismatched Cd<sub>1−x</sub>Be<sub>x</sub>Te semiconductor alloy: experiment and ab initio calculations.
- Authors
Elmahjoubi, A.; Shoker, M. B.; Pagès, O.; Torres, V. J. B.; Polian, A.; Postnikov, A. V.; Bellin, C.; Béneut, K.; Gardiennet, C.; Kervern, G.; En Naciri, A.; Broch, L.; Hajj Hussein, R.; Itié, J.-P.; Nataf, L.; Ravy, S.; Franchetti, P.; Diliberto, S.; Michel, S.; Abouais, A.
- Abstract
The emerging CdTe–BeTe semiconductor alloy that exhibits a dramatic mismatch in bond covalency and bond stiffness clarifying its vibrational-mechanical properties is used as a benchmark to test the limits of the percolation model (PM) worked out to explain the complex Raman spectra of the related but less contrasted Zn1−xBex-chalcogenides. The test is done by way of experiment ( x ≤ 0.11 ), combining Raman scattering with X-ray diffraction at high pressure, and ab initio calculations (x ~ 0–0.5; x ~1). The (macroscopic) bulk modulus B 0 drops below the CdTe value on minor Be incorporation, at variance with a linear B 0 versus x increase predicted ab initio, thus hinting at large anharmonic effects in the real crystal. Yet, no anomaly occurs at the (microscopic) bond scale as the regular bimodal PM-type Raman signal predicted ab initio for Be–Te in minority (x ~0, 0.5) is barely detected experimentally. At large Be content (x ~1), the same bimodal signal relaxes all the way down to inversion, an unprecedented case. However, specific pressure dependencies of the regular (x ~0, 0.5) and inverted (x ~1) Be–Te Raman doublets are in line with the predictions of the PM. Hence, the PM applies as such to Cd1−xBexTe without further refinement, albeit in a "relaxed" form. This enhances the model's validity as a generic descriptor of phonons in alloys.
- Subjects
AB-initio calculations; ALUMINUM-zinc alloys; SEMICONDUCTORS; RAMAN scattering; ALLOYS; DIFFRACTIVE scattering; BULK modulus
- Publication
Scientific Reports, 2023, Vol 13, Issue 1, p1
- ISSN
2045-2322
- Publication type
Article
- DOI
10.1038/s41598-023-39248-6