Emergent phenomena in correlated oxides close to metal-insulator transition
【Abstract】 Correlated oxides exhibit a wide range of exotic phenomena from metal-insulator transition, colossal magnetoresistance to high-temperature superconductivity. In this talk, we focus on one class of correlated oxides that are close to metal-insulator transition. Upon external perturbations, new phenomena emerge in those correlated oxides. Specifically, we show that: i) a magnetic transition can simultaneously induce an orbital-selective insulator-metal transition in rock-salt ordered oxides A2BB'O6 where B is a non-magnetic ion and B' a magnetic ion with a d3 electronic configuration (Ru5+ and Os5+). The orbital selectivity originates from geometrical frustration of a face-centered-cubic lattice on which the magnetic ions B' reside; ii) in (SrRuO3)_1/(SrTiO3)_N superlattices, the Ru magnetic anisotropy is changed from two-fold along <001> axis (N<3) to eightfold along <111> axis (N>=3). The reorientation of the Ru magnetic easy axis is due to a new orbital ordering which significantly tunes the underlying spin-orbit interaction.
【Bio】 Dr. Hanghui Chen is an Assistant Professor of Physics of NYU Shanghai and a Global Network Assistant Professor of NYU. Prior to joining NYU Shanghai, he was a post-doctoral fellow at Columbia University working with Professor Andrew Millis. He holds a Ph.D from Yale University and a B.S. from Peking University. Dr. Chen’s research interests lie in first-principles modelling and design of complex meta-materials, in particular transition metal oxides and their heterostructures.