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Chemical Bonding, Elasticity, And Valence Force Field Models: A Case Study For Α-Pt2si And Ptsi, Gus L. W. Hart, J. E. Klepeis, O. Beckstein, O. Pankratov
Chemical Bonding, Elasticity, And Valence Force Field Models: A Case Study For Α-Pt2si And Ptsi, Gus L. W. Hart, J. E. Klepeis, O. Beckstein, O. Pankratov
Faculty Publications
We have carried out a detailed study of the chemical bonding for two room-temperature stable platinum silicide phases, tetragonal α-Pt2Si. These elements of the bonding are further analyzed by constructing valence force field models using the results from recent first principles calculations of the six (nine) independent, nonzero elastic constants of α-Pt2Si (PtSi). The resulting volume-, radial-, and angular-dependent force constants provide insight into the relative strength of various bonding elements as well as the trends observed in the elastic constants themselves. The valence force field analysis yields quantitative information about the nature of the chemical bonding that is not …
Tunable Local Polariton Modes In Semiconductors, Michael G. Foygel, Alexey Yamilov, Lev I. Deych, Alexander A. Lisyansky
Tunable Local Polariton Modes In Semiconductors, Michael G. Foygel, Alexey Yamilov, Lev I. Deych, Alexander A. Lisyansky
Physics Faculty Research & Creative Works
We study the local states within the polariton band gap that arise due to deep defect centers with strong electron-phonon coupling. Electron transitions involving deep levels may result in alteration of local elastic constants. In this case, substantial reversible transformations of the impurity polariton density of states occur, which include the appearance/disappearance of the polariton impurity band, and its shift and/or the modification of its shape. These changes can be induced by thermo- and photoexcitation of the localized electron states or by trapping of injected charge carriers. We develop a simple model, which is applied to the Op center …