Anomalous asymmetry in the Fermi surface of the high-temperature superconductor YBa&lt;sub&gt;2&lt;/sub&gt;Cu&lt;sub&gt;4&lt;/sub&gt;O&lt;sub&gt;8&lt;/sub&gt; revealed by angle-resolved photoemission spectroscopy

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

doi:10.1103/PhysRevB.80.100505

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

Kondo 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

Citation

Kondo, T., Khasanov, R., Sassa, Y., Bendounan, A., Pailhes, S., Chang, J., … Kaminski, A. (2009). Anomalous asymmetry in the Fermi surface of the high-temperature superconductor YBa₂Cu₄O₈ revealed by angle-resolved photoemission spectroscopy. Physical Review B, 80(10), 100505 (4 pp.). https://doi.org/10.1103/PhysRevB.80.100505

Persistent URL https://www.dora.lib4ri.ch/psi/islandora/object/psi:17469

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.