Disappearance of Superconductivity and a Concomitant Lifshitz Transition in Heavily Overdoped Bi$_2$Sr$_2$CuO$_{6}$ Superconductor Revealed by Angle-Resolved Photoemission Spectroscopy
1Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190 2University of Chinese Academy of Sciences, Beijing 100049 3Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190 4Songshan Lake Materials Laboratory, Dongguan 523808 5Collaborative Innovation Center of Quantum Matter, Beijing 100871
Abstract：By partially doping Pb to effectively suppress the superstructure in single-layered cuprate Bi$_2$Sr$_2$CuO$_{6+\delta}$ (Pb-Bi2201) and annealing them in vacuum or in high pressure oxygen atmosphere, a series of high quality Pb-Bi2201 single crystals are obtained with $T_{\rm c}$ covering from 17 K to non-superconducting in the overdoped region. High resolution angle resolved photoemission spectroscopy measurements are carried out on these samples to investigate the evolution of the Fermi surface topology with doping in the normal state. Clear and complete Fermi surfaces are observed and quantitatively analyzed in all of these overdoped Pb-Bi2201 samples. A Lifshitz transition from hole-like Fermi surface to electron-like Fermi surface with increasing doping is observed at a doping level of $\sim$0.35. This transition coincides with the change that the sample undergoes superconducting-to-non-superconducting states. Our results reveal the emergence of an electron-like Fermi surface and the existence of a Lifshitz transition in heavily overdoped Bi2201 samples. This provides important information in understanding the connection between the disappearance of superconductivity and the Lifshitz transition in the overdoped region.
2019, Vol. 36 
