Atomic and Electronic Structures of Unreconstructed Polar MgO(111) Thin Film on Ag(111)

摘要

Atomic and electronic structures of a polar surface of MgO formed on Ag(111)was investigated by using reflection high energy electron diffraction (RHEED),Auger electron spectroscopy, electron energy loss spectroscopy (EELS), andultraviolet photoemission spectroscopy (UPS). A rather flat unreconstructedpolar MgO(111) 1$\times$1 surface could be grown by alternate adsorption of Mgand O$_{2}$ on Ag(111). The stability of the MgO(111) surface was discussed interms of interaction between Ag and Mg atoms at the interface, and charge stateof the surface atoms. EELS of this surface did not show a band gap region, andfinite density of states appeared at the Fermi level in UPS. These resultssuggest that a polar MgO(111) surface was not an insulating surface but asemiconducting or metallic surface.