1210.0662 (Oscar Grå näs et al.)

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

Oscar Grå näs, Biswanath Dutta, Subhradip Ghosh, Biplab Sanyal

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.

View original: http://arxiv.org/abs/1210.0662