Consideration of atom movement during Si surface reconstruction

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abstract
Si(111) surface reconstructions are classified into two families, the 2x2 family(2x2,c2x4,c2x8,*3x*3) and nxn DAS family. By in-situ atomic scale observation of Si(111) surface reconstruction and by a statistical argument on the nucleation of a daughter phase in Si(111) matrix, we have found that the 2x2 family is a result of random motion of adatoms on a Si(111)-1x1 substrate, while the nxn DAS family can never be formed only by the movement of adatoms but some coo\ perative movement of substratre Si atoms is necessary.

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Keywords; Si(111),Scanning Tunneling Microscopy; DAS structure;Random motion; Cooperative movement