Atomic structure of the Si(100)-(5x3)-Au surface

An atomic structure model for the 5 x 3 phase observed on annealing Au deposited on clean Si(100) surfaces at room temperature is proposed from an ultrahigh-vacuum transmission electron microscopy imaging and diffraction study. The basic structure is made of silicon and gold atoms arranged in four parallel rows on the surface, and two parallel rows of gold atoms in the third layer in the bulk. The spacing between these subsurface gold rows results in the application of a compressive strain to the two outer surface rows. A combination of such structural units arranged in 5 x 3 and root 26 x 3 geometries satisfactorily explains earlier scanning tunneling microscopy, and current transmission electron microscopy data.