Resonance of one-phonon and two-phonon states in mixed semiconductors

Artamonov, V. V.; Valakh, M. Ya.; Litvinchuk, A. P.; Sidorenko, V. I.; Yaremko, A. M.

doi:10.1007/bf00662747

“…We re-assign the presumed unique TO mode in the Raman/IR spectra of ZnTeSe as the sum of close T O Zn−Te and TO Se Zn−Se modes. In fact the bi-modal character was already obvious in the Raman spectra recorded by Artamonov et al 20 The intensities of the two modes in Fig. 4 exhibit antagonist variations versus x, and become equal at x∼0.7, consistently with experimental observations.…”

Section: (To Lo) Raman Lineshapessupporting

confidence: 85%

“…Representative sets of (TO, LO) frequencies in ZnTeSe obtained from Raman/IR analysis, as taken in the literature, 13,19,20 are displayed in Fig. 3.…”

Section: Percolation Picture For Znte1−xsexmentioning

confidence: 99%

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Unification of the phonon mode behavior in semiconductor alloys: Theory andab initiocalculations

Pagès¹,

Postnikov²,

Kassem³

et al. 2008

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We demonstrate how to overcome serious problems in understanding and classification of vibration spectra in semiconductor alloys, following from traditional use of the virtual crystal approximation (VCA). We show that such different systems as InGaAs (1-bond→1-mode behavior), InGaP (modified 2-mode) and ZnTeSe (2-bond→1-mode) obey in fact the same phonon mode behavior -hence probably a universal one -of a percolation-type (1-bond→2-mode). The change of paradigm from the 'VCA insight' (an averaged microscopic one) to the 'percolation insight' (a mesoscopic one) offers a promising link towards the understanding of alloy disorder. The discussion is supported by ab initio simulation of the phonon density of states at the zone-center of representative supercells at intermediary composition (ZnTeSe) and at the impurity-dilute limits (all systems). In particular, we propose a simple ab initio 'protocol' to estimate the basic input parameters of our semi-empirical 'percolation' model for the calculation of the 1-bond→2-mode vibration spectra of zincblende alloys. With this, the model turns self-sufficient.

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“…Representative sets of (TO, LO) frequencies in Zn-TeSe obtained from Raman/IR analysis, as taken in the literature, 13,19,20 are displayed in Fig. 3.…”

Section: Percolation Picture For Znte1−xsexmentioning

confidence: 99%

Unification Of The Phonon Mode Behavior In Semiconductor Alloys

Pagès¹,

Chafi²,

Souhabi³

et al. 2010

AIP Conference Proceedings

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We demonstrate how to overcome serious problems in understanding and classification of vibration spectra in semiconductor alloys, following from traditional use of the virtual crystal approximation (VCA). We show that such different systems as InGaAs (1-bond→1-mode behavior), InGaP (modified 2-mode) and ZnTeSe (2-bond→1-mode) obey in fact the same phonon mode behavior -hence probably a universal one -of a percolation-type (1-bond→2-mode). The change of paradigm from the 'VCA insight' (an averaged microscopic one) to the 'percolation insight' (a mesoscopic one) offers a promising link towards the understanding of alloy disorder. The discussion is supported by ab initio simulation of the phonon density of states at the zone-center of representative supercells at intermediary composition (ZnTeSe) and at the impurity-dilute limits (all systems). In particular, we propose a simple ab initio 'protocol' to estimate the basic input parameters of our semi-empirical 'percolation' model for the calculation of the 1-bond→2-mode vibration spectra of zincblende alloys. With this, the model turns self-sufficient.

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