Low-energy electron microscopy was used to clarify how the thermal decay of two-dimensional (2D) islands and 2D vacancy islands depends on the surface structure. Using the first-order 1x1–7x7 phase transition on Si(111), 2D islands were produced, with superheated 7x7 phases above the critical temperature Tc, and their decay kinetics were compared with those of islands with equilibrium surface phases of co-existing 1x1 and 7x7 structures. 2D vacancy islands with supercooled 1x1 phases were also compared with 2D vacancy islands with coexisting 1x1 and 7x7 phases below Tc. The superheated islands decay faster than the coexisting islands, indicating that the equilibrium adatom concentration, ceq, of the superheated island was higher than that of the coexisting island. The supercooled vacancy islands also decay faster than the coexisting vacancy islands, because the supercooled vacancy islands had lower ceq than coexisting vacancy islands. These differences in ceq give an estimate of the energy difference between the 1x1 and 7x7 structures.

Thermal Decay of Superheated 7x7 Islands and Supercooled 1x1 Vacancy Islands on Si(111). H.Hibino, Y.Watanabe, C.W.Hu, I.S.T.Tsong: Physical Review B, 2005, 72[24], 245424 (6pp)