Selective hybridization between the main band and the superstructure band in the Bi2Sr2CaCu2O8+δ superconductor
/ Authors
Q. Gao, Hongtao Yan, Jing Liu, Ping Ai, Yongqing Cai, Cong Li, Xiangyu Luo, Cheng Hu, C. Song, Jian-wei Huang
and 13 more authors
Hongtao Rong, Yuan–Biao Huang, Qingyang Wang, Guodong Liu, G. Gu, Feng-feng Zhang, Feng Yang, Shen-jin Zhang, Qin-jun Peng, Zu-Yan Xu, Lin Zhao, T. Xiang, X. Zhou
/ Abstract
High-resolution laser-based angle-resolved photoemission measurements have been carried out on Bi$_2$Sr$_2$CaCu$_2$O$_{8+\delta}$ (Bi2212) and Bi$_2$Sr$_{2-x}$La$_x$CuO$_{6+\delta}$ (Bi2201) superconductors. Unexpected hybridization between the main band and the superstructure band in Bi2212 is clearly revealed. In the momentum space where one main Fermi surface intersects with one superstructure Fermi surface, four bands are observed instead of two. The hybridization exists in both superconducting state and normal state, and in Bi2212 samples with different doping levels. Such a hybridization is not observed in Bi2201. This phenomenon can be understood by considering the bilayer splitting in Bi2212, the selective hybridization of two bands with peculiar combinations, and the altered matrix element effects of the hybridized bands. These observations provide strong evidence on the origin of the superstructure band which is intrinsic to the CuO$_2$ planes. Therefore, understanding physical properties and superconductivity mechanism in Bi2212 should consider the complete Fermi surface topology which involves the main bands, the superstructure bands and their interactions.
Journal: Physical Review B