Doping evolution of the charge excitations and electron correlations in electron-doped superconducting La2−xCexCuO4

DOI: 10.1038/s41535-019-0205-9

Authors: Jiaqi Lin (ShanghaiTech University; Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences; University of Chinese Academy of Sciences) , Jie Yuan (Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences) , Kui Jin (Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences; Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences) , Zhiping Yin (Beijing Normal University) , Gang Li (ShanghaiTech University) , Kejin Zhou (Diamond Light Source) , Xingye Lu (Beijing Normal University; Swiss Light Source) , Marcus Dantz (Swiss Light Source, Diamond Light Source) , Thorsten Schmitt (Swiss Light Source) , Hong Ding (Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences; University of Chinese Academy of Sciences) , Haizhong Guo (Zhengzhou University) , Mark P. M. Dean (Brookhaven National Laboratory) , Xuerong Liu (ShanghaiTech University)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Npj Quantum Materials , VOL 5

State: Published (Approved)
Published: January 2020

Abstract: Electron correlations play a dominant role in the charge dynamics of the cuprates. We use resonant inelastic X-ray scattering (RIXS) to track the doping dependence of the collective charge excitations in electron doped La 2−x 2−x Ce x x CuO 4 4 (LCCO). From the resonant energy dependence and the out-of-plane momentum dependence, the charge excitations are identified as three-dimensional (3D) plasmons, which reflect the nature of the electronic structure and Coulomb repulsion on both short and long lengthscales. With increasing electron doping, the plasmon excitations increase monotonically in energy, a consequence of the electron correlation effect on electron structure near the Fermi surface (FS). Importantly, the plasmon excitations evolve from a broad feature into a well-defined peak with much increased life time, revealing the evolution of the electrons from incoherent states to coherent quasi-particles near the FS. Such evolution marks the reduction of the short-range electronic correlation, and thus the softening of the Mottness of the system with increasing electron doping.

Journal Keywords: Superconducting properties and materials; Surfaces, interfaces and thin films

Subject Areas: Materials, Physics


Instruments: I21-Resonant Inelastic X-ray Scattering (RIXS)

Other Facilities: Swiss Light Source

Documents:
s41535-019-0205-9.pdf