INHIBITED AL DIFFUSION AND GROWTH ROUGHENING OF GA-COATED AL(100)

Ab initio calculations indicate that the ground state for Ga adsorptio n on Al(100) is on surface with local unit coverage. On Ga-coated Al(1 00), the bridge diffusion barrier for Al is large, but the Al --> Ga e xchange barrier is zero: the ensuing incorporation of randomly deposit ed Al's into the Ga: overlayer realizes a percolation network, efficie ntly recoated by Ca atoms. Based on calculated energetics, we predict rough surface growth at all temperatures; modeling the growth by a ran dom deposition model with partial relaxation, we find a power-law dive rgent roughness w similar to t(0.07+/-0.02).