Atomically resolved interface structure of a vanadium sesquioxide(0001) film grown on Cu_3Au(001)

摘要

Heterointerfaces between oxides and metals are of wide-ranging importance. High resolution transmission electron microscopy (HRTEM) with spherical aberration (Cs) image correction has been used to unravel the metal-oxide interface on an atomic scale. The method is exemplified at the interface of a thin two-dimensional monocrystalline film of V_2O_3(0001) grown on a Cu_3Au(001) sample. At the interface an extra vanadium monolayer is introduced between the part of the Cu_3Au substrate and the oxide layer. The location of the extra vanadium is not related with the V_2O_3 crystallography but instead connected to the Cu_3Au(001) metal side. The oxide layer ends at the interface with the quasi-hexagonal close packed oxygen layer of bulk truncated V_2O_3(0001). The stacking sequence of oxygen columns follows visibly the vanadium oxide part and is directionally decoupled from the Cu_3Au(001)-V region. The HRTEM images show not only the position of the metal atoms but clearly also the oxygen sites which makes this method well suited for the investigation of metal oxide interfaces.