Unoccupied electronic states of the high-temperature superconductor Bi2Sr2CaCu2O8 investigated by two-photon photoemission spectroscopy

Yasuyuki Sonoda; Toshiaki Munakata

doi:10.1103/PhysRevB.70.134517

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Unoccupied electronic states of the high-temperature superconductor Bi2Sr2CaCu2O8 investigated by two-photon photoemission spectroscopy

Yasuyuki Sonoda, Toshiaki Munakata

DOI 10.1103/PhysRevB.70.134517 · Physical Review B

T1

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Abstract

Two-photon photoemission spectroscopy (2PPES) has been applied to an optimally doped high-temperature superconductor (HTSC) Bi2Sr2CaCu2O8(Bi2212). 2PPES with photon energy between 4.0 and 4.9eV revealed four structures, labeled as A to D, arising from unoccupied states at <0.5, 1.8, 2.7, and 3.7eV above the Fermi level (EF), respectively. Structures A and B show no strong polarization dependence, whereas structures C and D appear in p-polarization configuration and completely disappear in s-polarization. The polarization dependence indicates that the unoccupied states for structures A and B are composed of orbitals parallel to the CuO2 plane. The unoccupied states for structures C and D are composed of atomic orbitals perpendicular to the CuO2 plane. Unoccupied states for structures A and B are attributed to the unoccupied band of carrier and the upper Hubbard band, respectively.

Source-reported materials — not catalogue approval

Formula	Reported Tc (K)	Pressure (GPa)	Type
Bi2Sr2CaCu2O8 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	90	Pressure not reported	unknown