Electronic and Magnetic Excitations of Cuprates La2-xSrxCuO4 Revealed by Soft X-ray RIXS
Amol Singh1*, Hsiao-Yu Huang1, Yen-Yi Chu1, Jun Okamoto1, Atsushi Fujimori3, Seiki Komiya4, Sumio Ishihara5, Wei Sheng Lee6, Chien-Te Chen1, Di-Jing Huang1,2
1National Synchrotron Radiation Research Center, 101 Hsin-Ann Road, Hsinchu 30076, Taiwan
2Department of Physics, National Tsing-Hua University, Hsinchu 30013, Taiwan
3Department of Physics, University of Tokyo, Hongo, Tokyo 113-0033, Japan
4Central Research Institute of Electric Power Industry, Komae, Tokyo 201-8511, Japan
5Department of Physics, Tohoku University, Sendai 980-8578, Japan
6SIMES, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
* Presenter:Amol Singh, email:rrcat.amol@gmail.com
The study of elementary excitations in cuprates is of great importance to reveal the spin fluctuations and the electron-phonon coupling in high-temperature superconductors. Here we report O K-edge resonant inelastic scattering X-ray scattering (RIXS) measurements to reveal charge-transfer, bi-magnon and phonon excitations in undoped and underdoped La2-xSrxCuO4. With an improved energy resolution of 25 meV, we observed charge-transfer excitons of Zhang-Rice spin singlet and bi-magnon excitations, which consist of coherent excitations involving spin flips of two neighboring sites with opposite direction. The energy and dispersion of the observed bi-magnon excitations lend support to the existence of magnon-magnon interaction is the undoped cuprate. Implications of these observed electronic excitations will be discussed in detail.

Keywords: RIXS, Cuprates, Superconductivity