Unconventional crystal field splitting in non-centrosymmetric BaTiO\(_3\) thin films

Understanding the crystal field splitting and orbital polarization in non-centrosymmetric systems such as ferroelectric materials is fundamentally important. In this study, taking BaTiO\(_3\) (BTO) as a representative material we investigate titanium crystal field splitting and orbital polarization in non-centrosymmetric TiO\(_6\) octahedra with resonant X-ray linear dichroism at Ti \(L_{2,3}\)-edge. The high-quality BaTiO\(_3\) thin films were deposited on DyScO\(_3\) (110) single crystal substrates in a layer-by-layer way by pulsed laser deposition. The reflection high-energy electron diffraction (RHEED) and element specific X-ray absorption spectroscopy (XAS) were performed to characterize the structural and electronic properties of the films. In sharp contrast to conventional crystal field splitting and orbital configuration (\(d_{xz}\)/\(d_{yz}\) \(