Quantum fluctuations of charge order in a cuprate superconductor unveiled by X-ray scattering
Hsiao-Yu Huang1*, Amol Singh1, Chung-Yu Mou2, Steven Johnston3, Jeroen van den Brink4, Peng-Jen Chen5, Ting-Kuo Lee5, Jun Okamoto1, Yen-Yi Chu1, Jung-Han Li2,1, Seiki Komiya6, A. C. Komarek7, Atsushi Fujimori8,1, Chien-Te Chen1, Di-Jing Huang1
1National Synchrotron Radiation Research Center, Hsinchu, Taiwan
2Department of Physics, National Tsing Hua University, Hsinchu, Taiwan
3Department of Physics and Astronomy, The University of Tennessee, Knoxville, USA
4Institute for Theoretical Solid State Physics, IFW Dresden, Dresden, Germany
5Institute of Physics, Academia Sinica, Taipei, Taiwan
6Central Research Institute of Electric Power Industry, Kanagawa, Japan
7Max Planck Institute for Chemical Physics of Solids, Dresden, Germany
8Department of Applied Physics, Waseda University, Tokyo, Japan
* Presenter:Hsiao-Yu Huang, email:huang.hy@nsrrc.org.tw
High-TC cuprate superconductors possess a variety of intertwined orders and a complex phase diagram. Quantum phase transitions play an important role in shaping this phase diagram. By using O K-edge resonant inelastic X-ray scattering (RIXS), we observed short-range charge density waves (CDWs) in the superconducting phase of La2−xSrxCuO4 (x = 0.15) near the optimal doping, and uncovered bond-stretching and bond-buckling phonon modes, which are coupled to the CDWs. With high-resolution RIXS results, we obtained spectral signature for quantum fluctuations of CDWs and revealed that the lifetime of particle-hole excitations in such quantum fluctuations reaches the universal limit of Planckian dissipation.

Keywords: High Tc curate superconductivity, Quantum fluctuation, Charge density wave, Resonant inelastic X-ray scattering