@article{303254d41c45488fa5f8516c0d9c399a,
title = "Revealing the Coulomb interaction strength in a cuprate superconductor",
abstract = "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.",
author = "Yang, {S. L.} and Sobota, {J. A.} and Y. He and Y. Wang and D. Leuenberger and H. Soifer and M. Hashimoto and Lu, {D. H.} and H. Eisaki and B. Moritz and Devereaux, {T. P.} and Kirchmann, {P. S.} and Shen, {Z. X.}",
note = "Publisher Copyright: {\textcopyright} 2017 American Physical Society.",
year = "2017",
month = dec,
day = "8",
doi = "10.1103/PhysRevB.96.245112",
language = "אנגלית",
volume = "96",
journal = "Physical Review B",
issn = "2469-9950",
publisher = "American Physical Society",
number = "24",
}