Interfaces as a Function of Film Thickness*

Second harmonic generation (SHG) is a well known optical technique for probing electronic symmetry originating from regions of broken symmetries. For La_0.67Sr_0.33MnO₃/SrTiO₃ (LSMO/STO) buried interfaces, rotational anisotropic SHG is capable of characterizing interfacial electronic symmetry. Using film thickness and growth conditions to control the interface structure for LSMO/STO buried interfaces, induced changes in the electronic symmetry are detected with rotational anisotropic SHG. Data accumulated for LSMO/STO demonstrates thickness-dependent enhanced four-fold electronic symmetry patterns which are contrary to the measured C_4v electronic symmetry measured using atomically resolved electron microscopy and spectroscopy. Furthermore, the relative angles of the peak intensities between in-plane and out-of-plane polarization geometries varies with film thickness. Rotational anisotropy SHG of LSMO/STO thin films will be presented from <5 unit cell to 300+ unit cell LSMO/STO heterostructures.