My work combining both physics and chemistry to create new types of electronic state of matter in oxide interfaces is essential, and I played a central role in the field. My contributions can be grouped in three different areas with selected examples:

(1) Discovery of quantum phenomena in extreme high mobility system by heterointerface design and modulation doping: (a) My group was the first to discover the modulation-doping at complex oxide interfaces by charge transfer [Nat. Mat. 14, 801 (2015)]. This enhances the electron mobility of oxide interface more than 100 times and results in the first observation of quantum Hall effect at 3d oxide interfaces [Phys. Rev. Letters 117, 096804 (2016)]. (b) We were also the first to discover a new type of 2DEG at spinel/perovskite oxide interfaces with world record high mobility [Nat. Comm. 4, 1371 (2013)]. The same samples also exhibit the largest ever discovered positive magnetoresistance of 80,000% [sub. Nat. Phys. 2019]. (c) The first discovery of metallic and insulating interfaces controlled by chemical redox reactions at oxide interfaces [Nano Letters, 11, 3774-3778 (2011)].

(2) Stability enhancement in ionic conductors by coherent interface design: Many researchers have tried repeatedly for many years to extend the stability of the δ-Bismuth oxide with partial success. I took another innovative path and stabilized the highly unstable δ-Bi2O3 by making atomically thin multilayered structure of Er2O3-stabilized δ-Bi2O3 (ESB) and Gadolinium oxide (Gd2O3) doped Ceria (CeO2) (GDC) achieving several orders of magnitude higher ion conductivity than all previous known ion conductors [Nat. Mat. 14, 500–504 (2015)]. This suggests a new strategy to design new materials [Oxide Roadmap: App. Sur. Sci. 482 (2019) 1–93].

(3) Mechanically tunable magnetism: A remarkable discovery that we made recently is that a mechanically tunable magnetic state coexists with high electron mobility [Nat. Phys. 15, 269–274 (2019)]. By using a tip of scanning SQUID microscopy to gently press down on the surface of the SrTiO3 and create a local force, he could change the configuration of the magnetic stripes at the surface drastically. The results point towards a delicate balance between the unperturbed magnetic order existing in the absence of stress and a ferromagnetic order induced by the stress. It is these latter results that I build upon in the present proposal and to a recent review paper on this topic.