Doping Evolution of Nodal Band Renormalization in Bi₂Sr₂CuO_6+δ Superconductor Revealed by Laser-Based Angle-Resolved Photoemission Spectroscopy

【摘要】 High resolution laser-based angle-resolved photoemission measurements are carried out on Bi₂Sr₂CuO_6+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 <10meV 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 T_c.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.更多还原

【Abstract】 High resolution laser-based angle-resolved photoemission measurements are carried out on Bi₂Sr₂CuO_6+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 <10meV 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 T_c.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.更多还原