|PLACE||Room 815, New Physics Building, NTU|
|FIELD||Computational Materials Research|
|SPEAKER||Dr. Shigeki Onoda - Condensed Matter Theory Lab., RIKEN, Japan|
|TITLE||Chiral spin order and electromagnetic dynamics in one-dimensional multiferroic cuprates|
|ABSTRACT||We show by unbiased numerical calculations that the ferromagnetic nearest-neighbor exchange interaction stabilizes a vector spin chiral order against the quantum fluctuation in a frustrated spin-1/2 chain relevant to multiferroic cuprates, LiCu2O2 and LiCuVO4. Our semi-classical analyses including inter-chain couplings for LiCu2O2 resolve controversies on the helical magnetic structure and unveil the pseudo-Nambu-Goldstone modes as the origin of experimentally observed electromagnons.
 S. Furukawa, M. Sato, and S. Onoda, Phys. Rev. Lett. 105, 257205 (2010).