Nanoscale structures formed in silicon cleavage studied with large-scale electronic structure calculations: Surface reconstruction, steps, and bending

The 10-nm-scale structure formed in silicon cleavage is studied by the quantum mechanical calculations of large-scale electronic structure. The cleavage process was simulated and the results show not only the elementary process of the (experimentally observed) (111)-(2x1) surface reconstruction but also several step-formation processes. These processes are studied by analyzing electronic freedom and compared with scanning tunneling microscopy experiments. The stability mechanism of the (111)-(2x1) cleavage mode is presented beyond the traditional approach with surface energy. In other results, the cleavage path was bent into the experimentally observed planes, owing to the relative stability among cleavage modes. Several common aspects between cleavage and other phenomena are discussed from the viewpoints of nonequilibrium process and 10-nm-scale structure.