Atomic and electronic structures of lattice mismatched Cu 2O/TiO2 interfaces

Publication Type:

Journal Article


Applied Physics Letters, American Institute of Physics Inc., Volume 104, Number 21 (2014)


Heterojunction interfaces between metal oxides are often highly lattice mismatched. The atomic and electronic structures of such interfaces, however, are not well understood. We have synthesized Cu2O/TiO2 heterojunction thin films with 13% lattice mismatch and studied the interface via experimental methods and large-scale density function theory calculations of supercells containing ∼1300 atoms. We find that an interface of epitaxial quality is formed via a coincidence site lattice of 8 Cu2O unit cells matching 9 TiO2 unit cells. Calculations reveal the existence of a dislocation core of the O sublattices at the interface and a random arrangement of one layer of interfacial Cu atoms. The interfacial electronic structure is found to be mostly determined by the interfacial Cu distribution, rather than by the O dislocation core. The conduction band minimum and valence band maximum states are spatially separated, and there is no strongly localized state near the core. © 2014 AIP Publishing LLC.


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