1. Atomic-layer-resolved composition and electronic structure of the cuprate Bi$_2$Sr$_2$CaCu$_2$O$_{8+��}$ from soft x-ray standing-wave photoemission
- Author
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Kuo, Cheng-Tai, Lin, Shih-Chieh, Conti, Giuseppina, Pi, Shu-Ting, Moreschini, Luca, Bostwick, Aaron, Meyer-Ilse, Julia, Gullikson, Eric, Kortright, Jeffrey B., Nem����k, Slavomir, Rault, Julien E., F��vre, Patrick Le, Bertran, Fran��ois, Santander-Syro, Andr��s F., Vartanyants, Ivan A., Pickett, Warren E., Saint-Martin, Romuald, Taleb, Amina, and Fadley, Charles S.
- Subjects
Superconductivity (cond-mat.supr-con) ,Condensed Matter::Materials Science ,Strongly Correlated Electrons (cond-mat.str-el) ,Condensed Matter::Superconductivity ,Materials Science (cond-mat.mtrl-sci) ,FOS: Physical sciences - Abstract
A major remaining challenge in the superconducting cuprates is the unambiguous differentiation of the composition and electronic structure of the CuO$_2$ layers and those of the intermediate layers. The large c axis for these materials permits employing soft x-ray (930.3 eV) standing wave (SW) excitation in photoemission that yields atomic layer-by-atomic layer depth resolution of these properties. Applying SW photoemission to Bi$_2$Sr$_2$CaCu$_2$O$_{8+��}$ yields the depth distribution of atomic composition and the layer-resolved densities of states. We detect significant Ca presence in the SrO layers and oxygen bonding to three different cations. The layer-resolved valence electronic structure is found to be strongly influenced by the supermodulation structure--as determined by comparison to DFT calculations, by Ca-Sr intermixing, and by the Cu 3d-3d Coulomb interaction, further clarifying the complex interactions in this prototypical cuprate. Measurements of this type for other quasi-two-dimensional materials with large-c represent a promising future direction., 22 pages, 5 figures, plus Supplemental Material (15 pages)
- Published
- 2018
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