Emergent Phenomena at Oxide Interfaces
The plethora of fascinating properties observed in oxide heterostructures has attracted a lot of interest. Most noticeably, the confined electron gas formed at the interface between the two insulators LaAlO3 and SrTiO3 features e.g. gate-tunable superconductivity, ferromagnetism and non-volatile memory effects. Numerous studies have been devoted to understanding the origin of the conductivity along with enhancing its properties. Recently, we found that substituting LaAlO3 with γ-Al2O3 can produce a confined electron gas with an electron mobility exceeding 100,000 cm2/Vs. Here, I show that the γ-Al2O3/SrTiO3 interface conductivity originates from oxygen vacancies and use defect engineering to control various interface properties. In addition, I find that the high mobility coexists with a strain-tunable magnetic order below 40 K and a positive, non-saturating magnetoresistance of up to 80,000% at 15 T. The study evidences that the γ-Al2O3/SrTiO3 heterostructure is an exciting alternative to LaAlO3/SrTiO3 and paves the way for combining lattice, spin and electronic degrees of freedom.