Kondo scattering in δ-doped LaTiO3/SrTiO3 interfaces: Renormalization by spin-orbit interactions

We present a study of delta doping at the LaTiO3/SrTiO3 interface with isostructural antiferromagnetic perovskite LaCrO3 that dramatically alters the properties of the two-dimensional electron gas at the interface. The effects include a reduction in sheet-carrier density, prominence of the low-temperature resistivity minimum, enhancement of weak antilocalization below 10 K, and observation of a strong anisotropic magnetoresistance (MR). The positive and negative MR for out-of-plane and in-plane fields, respectively, and the field and temperature dependencies of MR suggest Kondo scattering by localized Ti3+ moments renormalized by spin-orbit interaction at T < 10 K, with the increased delta-layer thickness. Electron-energy-loss spectroscopy and density functional calculations provide convincing evidence of blocking of electron transfer from LTO to STO by the delta layer.