| Autor: |
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. |
| Rok vydání: |
2017 |
| Předmět: |
|
| Zdroj: |
Phys. Rev. B 96, 245112 (2017) |
| Druh dokumentu: |
Working Paper |
| DOI: |
10.1103/PhysRevB.96.245112 |
| Popis: |
We study optimally doped Bi$_{2}$Sr$_{2}$Ca$_{0.92}$Y$_{0.08}$Cu$_{2}$O$_{8+\delta}$ (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. |
| Databáze: |
arXiv |
| Externí odkaz: |
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