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Anomalous asymmetry in the Fermi surface of the high-temperature superconductor YBa2Cu4O8 revealed by angle-resolved photoemission spectroscopy

Takeshi Kondo, R. Khasanov, Y. Sassa, A. Bendounan, S. Pailhes, J. Chang, J. Mesot, H. Keller, N. D. Zhigadlo, M. Shi, Z. Bukowski, J. Karpinski, A. Kaminski

DOI 10.1103/PhysRevB.80.100505 · Physical Review B

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Abstract

We use microprobe angle-resolved photoemission spectroscopy to study the Fermi surface and band dispersion of the CuO2 planes in the high-temperature superconductor, YBa2Cu4O8. We find a strong in-plane asymmetry of the electronic structure between directions along a and b axes. The saddle point of the antibonding band lies at a significantly higher energy in the a direction (π,0) than the b direction (0,π), whereas the bonding band displays the opposite behavior. We demonstrate that the abnormal band shape is due to a strong asymmetry of the bilayer band splitting, likely caused by a nontrivial hybridization between the planes and chains. This asymmetry has an important implication for interpreting key properties of the Y-Ba-Cu-O family, especially the superconducting gap, transport, and results of inelastic neutron scattering.

Source-reported materials — not catalogue approval

FormulaReported Tc (K)Pressure (GPa)Type
YBa2Cu4O8

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80Pressure not reportedunknown
YBa2Cu3O7-δ

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—Pressure not reportedunknown
Bi2Sr2CaCu2O8+δ

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—Pressure not reportedunknown
Bi2Sr2CuO6+δ

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—Pressure not reportedunknown
La2-xSrxCuO4

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—Pressure not reportedunknown

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