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

TitleAnomalous asymmetry in the Fermi surface of the high-temperature superconductor YBa2Cu4O8 revealed by angle-resolved photoemission spectroscopy
Publication TypeJournal Article
Year of Publication2009
AuthorsKondo T, Khasanov R, Sassa Y, Bendounan A, Pailhes S, Chang J, Mesot J, Keller H, Zhigadlo ND, Shi M, Bukowski Z, Karpinski J, Kaminski A
Journal TitlePhysical Review B
Volume80
Pages100505
Date Published11/01
ISBN Number1098-0121
Accession NumberISI:000270383100015
Keywordsanisotropy, cuprate superconductors, fluctuations, phase, point, spectra, spin, symmetry, yba2cu3o6.6, yba2cu3o7-delta
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 (pi, 0) than the b direction (0, pi), 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.
URL<Go to ISI>://000270383100015
DOI10.1103/Physrevb.80.100505