Transition between two patterns on an Au-deposited Si(111) surface

Two distinct patterns have been observed by depositing sub-monolayer Au onto a Si(111)-(7$\times $7) surface with a small miscut angle. Upon depositing Au at 600\r{ }C, we find that a stripe of (5$\times $2) reconstruction forms at the upper step edge in every terrace. For 700\r{ }C deposition, one entire terrace out of several terraces transforms into the (5$\times $2) reconstruction while the other terraces are totally unaffected by the Au deposition. The relative population between the (5$\times $2) and the (7$\times $7) terrace is governed by the amount of deposited Au. After annealing at a temperature above 700\r{ }C the striped (5$\times $2) pattern transforms into the (5$\times $2)-terrace pattern. The similarity between this ?coarsening? of (5$\times $2) reconstruction and the Ostwald ripening of clusters is striking and will be discussed. One application using the (5$\times $2) pattern as a template to grow nanostructure in designated regions will be demonstrated.