Doping Evolution of Nodal Band Renormalization in Bi2Sr2CuO6+δ Superconductor Revealed by Laser-Based Angle-Resolved Photoemission Spectroscopy
PENG Ying-Ying1, MENG Jian-Qiao1, ZHAO Lin1, LIU Yan1, HE Jun-Feng1, LIU Guo-Dong1, DONG Xiao-Li1, HE Shao-Long1, ZHANG Jun1, CHEN Chuang-Tian2, XU Zu-Yan2, ZHOU Xing-Jiang1**
1National Laboratory for Superconductivity, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190 2Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190
Abstract：High resolution laser-based angle-resolved photoemission measurements are carried out on Bi2Sr2CuO6+δ superconductor covering a wide doping range from heavily underdoped to heavily overdoped samples. Two obvious energy scales are identified in the nodal dispersions: one is the well-known 50–80 meV high energy kink and the other is <10 meV low energy kink. The high energy kink increases monotonously in its energy scale with increasing doping and shows weak temperature dependence, while the low energy kink exhibits a non-monotonic doping dependence with its coupling strength enhanced sharply below Tc. These systematic investigations on the doping and temperature dependence of these two energy scales favor electron-phonon interactions as their origin. They point to the importance in involving the electron-phonon coupling in understanding the physical properties and the superconductivity mechanism of high temperature cuprate superconductors.
2013, Vol. 30 
