Scanning tunneling microscopy and spectroscopy studies on structural and electronic properties of thin films of Co oxides and oxide precursor states on Ag(001)

Abstract

The main aim of this work is the electronic characterization of various Co oxide and precursor states on Ag(001), which grow during reactive deposition by evaporating Co from a Knudsen cell in an O 2 atmosphere. We have identified double-layer CoO(001) and monolayer and double-layer CoO(111), which show distinct differences in the I/ U and (d I/d U)/( I/ U) characteristics of scanning tunneling microscopy (STM)/scanning tunneling spectroscopy (STS). CoO(001) and, to some extent, also double-layer CoO(111) exhibit oxidic behavior. For CoO(001), the oxidic character is particularly recognized in the contrast dependence as a function of sample bias U.