Profile

Nini Pryds is a Professor and head the research section ‘Functional Oxide Materials’ at the Department of Energy Conversion and Storage, The Technical University of Denmark (DTU), where he leads a group of 25+ researchers working in the field of memristors, piezoelectricity, thermoelectricity, electrostriction and functional oxide thin films. He has made major contributions in emerging disciplines such as Nanoionics and Iontronics, dealing with the design and control of interface-related phenomena in fast ionic and electronic conductors.

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.