Distinct Superconducting Gap on Two Bilayer-Split Fermi Surface Sheets in $Bi_2Sr_2CaCu_2O_{8+\delta}$ Superconductor

Ping Ai; Qiang Gao; Jing Liu; Yuxiao Zhang; Cong Li; Jiangwei Huang; Chunyao Song; Hongtao Yan; Lin Zhao; Guodong Liu; Genda Gu; Fengfeng Zhang; Feng Yang; Qinjun Peng; Zuyan Zu; X. J. Zhou

doi:10.1088/0256-307x/36/6/067402

arXiv · 1905.04019

Distinct Superconducting Gap on Two Bilayer-Split Fermi Surface Sheets in $Bi_2Sr_2CaCu_2O_{8+\delta}$ Superconductor

Ping Ai·Qiang Gao·Jing Liu·Yuxiao Zhang·Cong Li·Jiangwei Huang·Chunyao Song·Hongtao Yan·Lin Zhao·Guodong Liu·Genda Gu·Fengfeng Zhang·Feng Yang·Qinjun Peng·Zuyan Zu·X. J. Zhou

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Abstract

High resolution laser-based angle-resolved photoemission measurements were carried out on an overdoped $Bi_2Sr_2CaCu_2O_{8+\delta}$ superconductor with a Tc of 75 K. Two Fermi surface sheets caused by bilayer splitting are clearly identified with rather different doping levels: the bonding sheet corresponds to a doping level of 0.14 which is slightly underdoped while the antibonding sheet has a doping of 0.27 that is heavily overdoped, giving an overall doping level of 0.20 for the sample. Different superconducting gap sizes on the two Fermi surface sheets are revealed for the first time. The superconducting gap on the antibonding Fermi surface sheet follows a standard d-wave form while it deviates from the standard d-wave form for the bonding Fermi surface sheet. The maximum gap difference between the two Fermi surface sheets near the antinodal region is $\sim$2 meV. These observations provide important information for studying the relationship between the Fermi surface topology and superconductivity, and the layer-dependent superconductivity in high temperature cuprate superconductors.

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Ping Ai, Qiang Gao, Jing Liu, Yuxiao Zhang, Cong Li, Jiangwei Huang, Chunyao Song, Hongtao Yan, Lin Zhao, Guodong Liu, Genda Gu, Fengfeng Zhang, Feng Yang, Qinjun Peng, Zuyan Zu, X. J. Zhou. 2019-05-10. Distinct Superconducting Gap on Two Bilayer-Split Fermi Surface Sheets in $Bi_2Sr_2CaCu_2O_{8+\delta}$ Superconductor. https://doi.org/10.1088/0256-307x%2F36%2F6%2F067402

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