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Spatial Distribution And Magnetism In Poly-Cr-Doped Gan From First Principles, X. Y. Cui, Julia E. Medvedeva, B. Delley, C. Stampfl, Arthur J. Freeman

Physics Faculty Research & Creative Works

Large scale density-functional theory calculations have been performed to understand the spatial distribution and magnetic coupling of Cr-doped GaN, in which exhaustive structural and magnetic configurations have been investigated by doping of up to five Cr atoms in large supercells. Our results provide direct evidence that the distribution of the doped magnetic ions is neither homogeneous nor random as widely assumed previously. Rather, under both Ga-rich and N-rich growth conditions, the Cr atoms have a strong tendency to form substitutional, embedded clusters with short-range magnetic interactions maintaining the wurtzite structure. Significantly, while the ferromagnetic state is favored for pair doping, …