Fabrication of polar CoO(1 1 1) thin films on Pt(1 1 1)

Atomic and electronic structures of a CoO(1 1 1) thin film on Pt(1 1 1) was studied using reflection high energy electron diffraction (RHEED), Auger electron spectroscopy (AES), electron energy loss spectroscopy (EELS), X-ray photoelectron spectroscopy (XPS), and ultraviolet photoelectron spectroscopy (UPS). The RHEED results indicated that a rather flat unreconstructed polar CoO(1 1 1) surface was grown on a Pt(1 1 1) substrate. The results of EELS and UPS for the CoO (1 1 1) surface suggested existence of low energy excitations originating from finite density of states at the Fermi level. These states could be ascribed to the shifted O-derived band in the CoO(1 1 1) surface layer.