Center for Correlated Electron Systems

Seminar

Spin, Dipole, and Lattice for Materials Genome, Geometric Frustration, and Dynamic High-k Catalysts

December 9, 2015l Hit 898
Date : December 17, 2015 15:00 ~ 16:00
Speaker : Dr.Jun Hee Lee(Ulsan National Institute of Science & Technology (UNIST))
Location : Bldg. 19, Rm. 210
The strong interplay of order parameters such as spin, electric dipole, and lattice in strongly-correlated electron oxides creates novel phenomena such as multiferroicity and geometric frustration, and can be coupled to surface chemistry.
First, we talk about the interplay in the multiferroic 3d [1] and 5d [2] oxides. We recently discovered multiple-order-parameters transition where all the materials properties are simultaneous flipped to the extremely opposite phases and drive drastic phase transitions [3,4,5]. Based on the extreme transitions, we launch a new research program “Quantum Materials Genome” discovering totally news phases out of conventional materials. Also we will talk about optical diode effect in multiferroic oxides utilizing the transition.  Second, we show a spinel where magnetic frustration drives new phases. By combining DFT with spin dynamics, we uncover spin-liquid like phases induced by the competition between localized and itinerant electrons in a geometrically-frustrated system Mn1-xCoxV2O4 [6]. Third, we show quantum paraelectrics (QP) such as SrTiO3 with huge dielectric constant can be easily coupled to various photo-electro-chemical reactions such as water splitting. Giant dielectric response of QP to molecular electric field from chemical reactants induces transient but huge polarizations in SrTiO3 by light. This dynamically-induced polarization critically lowers problematic rate-limiting steps and speeds up various photochemical reactions on thin-film oxides