Schedule Nov 06, 2009
Wannier Function Based First Principles Method for Disordered Systems
Tom Berlijn (SUNY/BNL)

Tom Berlijn1,2, Wei Ku1,2
1Stony Brook University
2Brookhaven National Laboratory

Title: Wannier Function Based First Principles Method for Disordered Systems

Abstract

A new affordable and accurate first principles method for studying disordered systems will be presented. When the influence of an impurity is expanded to lowest order in change of density, it becomes additive. Based on this principle one can obtain the influence of a single impurity and use linear superposition to obtain an effective Hamiltonian of a super cell that contains hundreds of disorered impurities. The actual distributions of impurities, commonly ignored in current methods as VCA and CPA, are now fully taken into account. This opens the possibility of studying the effect of multiple scattering of impurity clusters. Two case studies will be presented, NaxCoO2 and Zn1-xCuxO1-y, in which multiple scattering gives rise to weak and strong localization respectively.


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