Anomalous asymmetry of the Fermi surface in the YBa2Cu4O8 high temperature superconductor 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; S. M. Kazakov; J. Karpinski; A. Kaminski

arXiv · 0903.2218

Anomalous asymmetry of the Fermi surface in the YBa2Cu4O8 high temperature superconductor 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·S. M. Kazakov·J. Karpinski·A. Kaminski

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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 (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 non-trivial hybridization between the planes and chains. This asymmetry has an important implication for interpreting key properties of the Y-Ba-Cu-O (YBCO) family, especially the superconducting gap, transport and results of inelastic neutron scattering.

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Takeshi Kondo, R. Khasanov, Y. Sassa, A. Bendounan, S. Pailhes, J. Chang, J. Mesot, H. Keller, N. D. Zhigadlo, M. Shi, S. M. Kazakov, J. Karpinski, A. Kaminski. 2009-03-12. Anomalous asymmetry of the Fermi surface in the YBa2Cu4O8 high temperature superconductor revealed by Angle Resolved Photoemission Spectroscopy. https://arxiv.org/abs/0903.2218

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