Seminars Archive

Surface structure and electronic properties of rare-earth silicides epitaxially grown on Si(111)

Abstract
Although rare-earth silicides epitaxially grown on Si(111) are very interesting for its potential technological applications (extremely low value of the Schottky barrier height, 0% of lattice mismatch at the interface, very low reactivity), the surface atomic and electronic structure is nowadays under discussion. These materials exhibit two-dimensional electronic properties, as we have evidenced by Fermi surface measurements performed with synchrotron radiation photoemission spectroscopy. The surface character in the electronic structure is not well understood and it is likely originated by the layered atomic structure of the system. The LEED pattern shows a (V3xV3)R30 symmetry. Two atomic models for the surface termination have been previously proposed to account for this symmetry. These models are based on high energy photoelectron diffraction (XPD) experiments and STM images. However, a deeper examination of STM images measured at low voltages have allowed us to propose a third model, which has been recently corroborated by pseudo-potential calculations.