The effect of dopant-dopant interactions upon diffusion was modelled firstly at the quantum-chemical level. The relationship between atomic-scale results and macroscopic behavior was then obtained by assuming that interactions between molecular orbitals could be transmitted over hundreds of lattice spacings. Additional flux components were generated which modified the usual form of Fick's second law.

S.Aronowitz: Journal of Applied Physics, 1991, 69[7], 3901-6