Anti-Localization in Oxide Heterostructures

This thesis investigates the phenomenon of Anderson anti-localization in oxide heterostructures. The strong spin--orbit coupling in many two-dimensional oxide materials appears in form of a weak anti-localization signature in magneto-transport. This signature depends significantly on microscopic details of the relevant spin relaxation mechanism, but has often been misinterpreted in the literature. This thesis clarifies the different microscopic pictures and selects suitable fitting formulas. Beyond conventional weak anti-localization theory, which involves spin-1/2 particles, this thesis provides a closed form result for the magneto-transport of spin-3/2 states. This four-level system offers a generic model for a multiband weak anti-localization theory and identifies the coupling between Landau levels in the quintet and septet channel of the Cooperon as a key mechanism for the specific signature in magneto-transport. Furthermore, weak anti-localization in oxide heterostructures is often obfuscated by the multiband Hall effect. A numerical analysis is developed that singles out the weak anti-localization contribution self-consistently. This analysis is successfully applied to data obtained from the LaAlO3/SrTiO3 heterostructure, identifying the spin structure at the Fermi surface and revealing an unexpected hole-like charge carrier. The spin structure is also analyzed for magneto-transport data recently obtained from thin monolayers of BaPbO3 on SrTiO3. The so far undetected symplectic-metal--insulator transition is proposed for this structure and related materials, due to strong spin--orbit coupling, high charge carrier density, and single band behavior