Revealing the Coulomb interaction strength in a cuprate superconductor

作     者：Yang, S.-L. Sobota, J.A. He, Y. Wang, Y. Leuenberger, D. Soifer, H. Hashimoto, M. Lu, D.H. Eisaki, H. Moritz, B. Devereaux, T.P. Kirchmann, P.S. Shen, Z.-X. 

作者机构：Stanford Institute for Materials and Energy Sciences SLAC National Accelerator Laboratory 2575 Sand Hill Road Menlo ParkCA94025 United States Geballe Laboratory for Advanced Materials Departments of Physics and Applied Physics Stanford University StanfordCA94305 United States Advanced Light Source Lawrence Berkeley National Laboratory BerkeleyCA94720 United States Stanford Synchrotron Radiation Lightsource SLAC National Accelerator Laboratory 2575 Sand Hill Road Menlo ParkCA94025 United States Electronics and Photonics Research Institute National Institute of Advanced Industrial Science and Technology TsukubaIbaraki305-8558 Japan 

出 版 物：《arXiv》 (arXiv)

年 卷 期：2017年

核心收录：

主　　题：Charge transfer 

摘      要：We study optimally doped Bi2Sr2Ca0.92Y0.08Cu2O8+δ (Bi2212) using angle-resolved two-photon photoemission spectroscopy. Three spectral features are resolved near 1.5, 2.7, and 3.6 eV above the Fermi level. By tuning the photon energy, we determine that the 2.7 eV feature arises predominantly from unoccupied states. The 1.5 and 3.6 eV features reflect unoccupied states whose spectral intensities are strongly modulated by the corresponding occupied states. These unoccupied states are consistent with the prediction from a cluster perturbation theory based on the single-band Hubbard model. Through this comparison, a Coulomb interaction strength U of 2.7 eV is extracted. Our study complements equilibrium photoemission spectroscopy and provides a direct spectroscopic measurement of the unoccupied states in cuprates. The determined Coulomb U indicates that the charge-transfer gap of optimally doped Bi2212 is 1.1 eV. Copyright © 2017, The Authors. All rights reserved.