Theoretical study of the structural properties of the Si(0 0 1)-c(4 × 2) surface and the formation of its STM images

We present the theoretical study of the atomic geometry and electronic structure of the Si(0 0 1)-c(4 × 2) surface, and the numerical simulations of its scanning tunneling microscopy (STM) images and spatially resolved scanning tunneling spectroscopy (STS) spectra. The recent STM and STS measurements show that the interpretation of the basic features that appear in LDOS surface distribution above Fermi level is still controversial. In particular, it is not clear if the peak at +1.0 eV, that was previously interpreted as an upper edge of the band formed by π* surface states really originates from these states. Our theoretical study addresses this problem. To clarify this point we have performed LDA-MD calculations of the geometry and electronic structure of the Si(0 0 1)-c(4 × 2) surface, followed by a detailed theoretical analysis of the formation of STM images and STS spectra. The same analysis has also been performed for the occupied states of this system.