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

作者：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

来源：Physical Review B, 2009, 80(10): 100505.

DOI：10.1103/PhysRevB.80.100505

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.

• 出版日期2009-9
• 单位中国地震局