Regular step distribution of the bare Si(553) surface

Vicinal Si(111) surfaces are known to undergo faceting when the temperature is lowered below the (1x1) to (7x7) phase transition temperature. Depending on the cutoff angle value and direction with respect to the crystallographic axis, various facets, together with low Miller index terraces, are formed. Here, we report the formation of regularly distributed steps over macroscopic sample regions of the bare Si(553) surface. The surface morphology is studied with scanning tunneling microscopy and reflection high energy electron diffraction techniques. The (111) terraces of 2.88 nm in width, which are separated by double atomic height steps, reveal an unusual reconstruction. However, the electronic structure determined with angle resolved photoemission spectroscopy shows bands very similar to those observed for the Si(111)-(7x7) surface.