A new variational model was presented for computing the electronic first-order density matrix of a crystalline material in the presence of a local defect. A natural means of obtaining variational discretizations of the model was to expand the difference between the density matrix of the defective crystal and the density matrix of the perfect crystal; on the basis of pre-computed maximally localized Wannier functions of the perfect reference crystal. This approach could be used within the framework of any semi-empirical or density functional theory.

Non-Perturbative Embedding of Local Defects in Crystalline Materials. E.Cancès, A.Deleurence, M.Lewin: Journal of Physics - Condensed Matter, 2008, 20[29], 294213