Uniaxial strain induced band splitting in semiconducting SrTiO₃

We use angle-resolved photoemission spectroscopy to study the influence of mechanically induced uniaxial strain on the electronic structure of the oxide semiconductor SrTiO₃. We observe an orbital splitting between the Ti 3d_yz and 3d_xy bands, which are degenerate when unperturbed. Using the k·p method, we qualitatively explain the direction and the size of the observed energy splitting. Our comprehensive understanding of band splitting explains the strain induced mobility enhancement of electron-doped SrTiO3₃ in terms of band degeneracy breaking and reduced interband scattering. Our approach can be extended to differently strained oxide systems.