title: A new first principles approach to  calculate phonon spectra of disordered  alloys.
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 paper, a new first principles approach based on special quasirandom structures and an itinerant coherent potential approximation to compute the phonon spectra of such alloys is proposed and applied to Ni₀.₅Pt₀.₅ alloy. The agreement between our results and 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.
authors.affiliation: Department of Physics and Astronomy, Uppsala University, Box-516, SE-75120 Uppsala, Sweden.
authors.forename: Oscar
authors.initials: O
authors.lastname: Grånäs
authors.forename: Biswanath
authors.initials: B
authors.lastname: Dutta
authors.forename: Subhradip
authors.initials: S
authors.lastname: Ghosh
authors.forename: Biplab
authors.initials: B
authors.lastname: Sanyal