Surface double-layer structure in (110) oriented BiFeO3 thin film

Surface double-layer structure different from the interior was found in BiFeO3 thin film grown on SrRuO3 covered SrTiO3 (110) substrate by pulsed laser deposition. It was shown that BiFeO3 film exhibits epitaxial phase with single domain. X-ray reflectivity and X-ray photoelectron spectroscopy results revealed a skin layer of less than 1 nm with a reduced electron density and different surface state. Grazing incidence x-ray diffraction convinced a surface multi-domain structure of several nm beneath the surface skin layer. The double-layer near surface structure would be originated from the large depolarization field produced by the single-domain structure with strain. (C) 2014 AIP Publishing LLC.