Spontaneous fluctuation between symmetric and buckled dimer domains of Si(100) at 80 K

At 80 K, not all the dimers of Si(100) appear buckled in the scanning tunneling microscopy (STM) images but a certain number of the dimers arc observed in a symmetric configuration. We report on observations of a two-dimensional spontaneous fluctuation of the symmetric⇔buckled dimer domains at some particular locations. We interpret the spontaneous fluctuation to be induced by the competition of several antiphased c(4 × 2) buckled domains to expand. The fluctuation of domains was interpreted by two mechanisms: a fast switching between buckled dimer domains; and symmetric dimers induced by migration of P defects.