Based upon first-principles calculations within density functional theory, a kinetic pathway was proposed for Mn incorporation on reconstructed 2x2-T4 GaN(00•1), characterized by concerted substitution of a Ga atom by a Mn adatom via a precursor surface site T4. The Mn dopants at low densities were randomly distributed, resulting in intrinsic diluted magnetic semiconductors. At high Mn densities, planar ferromagnetic clusters oriented in the (00•1) plane could be readily formed at relatively low growth temperatures, but ferrimagnetic zig-zag columns along the growth orientation will be formed at high temperatures. Furthermore,

intrinsic diluted magnetic semiconductors were more likely to be formed via co-deposition of Mn+Ga+N at high growth rates. These findings help to explain the observed variations in both the magnetic ordering temperature TC and the magnetic nature of Ga1-xMnxN.

Concerted Diffusion, Clustering, and Magnetic Properties of Mn Dopants on a 2x2-T4 GaN(0001) Substrate. S.Hao, Z.Zhang: Physical Review Letters, 2007, 99[16], 166101