Doping and Momentum-Dependent Scattering Rate in Bi2201 Superconductor Measured By Laser-ARPES

We will present our high-resolution laser-based angle-resolved photoemission (ARPES) measurements on electron scattering rate in Bi₂Sr₂CuO₆ (Bi2201) superconductors over a wide doping range. With substitution of lead (Pb) and high oxygen pressure annealing, overdoped and heavily overdoped Pb-doped Bi2201 single crystals have been prepared. Underdoped and optimally doped Bi2201 samples have been obtained by lanthanum(La) substitution and flowing oxygen annealing. Laser-based ARPES measurements with super-high energy and momentum resolutions have been carried out to study the electron scattering rate as a function of momentum and temperature for Bi2201 over a wide range of doping levels. The implication of these results on understanding the anomalous normal state properties of the high temperature cuprate superconductors will be discussed.