“Tilt engineering of 4d and 5d transition metal oxides?”

Oct. 07 (Fri), 4:00 PM, E6-2. #1323(1st fl.)
Dr. Choong Hyun Kim,IBS-CCES, Seoul National University

Functional octahedral tilting has become a novel concept in multifunctional perovskite oxides, showing great potential for property manipulation and device design. Strong coupling between spins, orbitals and lattices in transition metal oxides are responsible for these features. Fundamental understanding of such phenomena requires detailed microscopic information on each physical degree of freedom for different physical qualities of spin, orbital, and lattice. In this presentation, we discuss spin-orbital-lattice cross-coupling phenomena in layered 4d ruthenates and 5d iridates. At first, single-layer ruthenates, Sr_{2-x}Ca_{x}RuO4 have interesting phase diagram including unconventional superconductor, metal-insulator transition, spin and orbital ordering. And these are strongly coupled to octahedral tilting distortion. Here we report interesting experimental observations including THz pump-probe optical spectroscopy and ARPES. Secondly, we will focus on control of magnetism in single-and bi-layer iridates via structural distortion. Due to its exotic nature of magnetism in iridates, they are strongly coupled to structural distortion and we can control and even induce spin flop or magnetization reversal phenomena in this series of compounds.

Contact: MyungJoon Han, Physics Dept., (mj.han@kaist.ac.kr)