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arXiv · 1210.0662

A new first principles approach to calculate phonon spectra of disordered alloys

Oscar Grånäs·Biswanath Dutta·Subhradip Ghosh·Biplab Sanyal
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Abstract

The lattice dynamics in substitutional disordered alloys with constituents having large size differences is driven by strong disorder in masses, inter-atomic force constants and local environments. In this letter, a new first-principles approach based on special quasi random structures and itinerant coherent potential approximation to compute the phonon spectra of such alloys is proposed and applied to Ni$_{0.5}$Pt$_{0.5}$ alloy. The agreement between our results with the experiments is found to be much better than for previous models of disorder due to an accurate treatment of the interplay of inter-atomic forces among various pairs of chemical species. This new formalism serves as a potential solution to the longstanding problem of a proper microscopic understanding of lattice dynamical behavior of disordered alloys.

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Oscar Grånäs, Biswanath Dutta, Subhradip Ghosh, Biplab Sanyal. 2012-10-02. A new first principles approach to calculate phonon spectra of disordered alloys. https://doi.org/10.1088/0953-8984%2F24%2F1%2F015402

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