Disappearance of Superconductivity and a Concomitant Lifshitz Transition in Heavily Overdoped Bi ₂ Sr ₂ CuO ₆ Superconductor Revealed by Angle-Resolved Photoemission Spectroscopy

Abstract

By partially doping Pb to effectively suppress the superstructure in single-layered cuprate Bi 2 Sr 2 CuO 6+δ (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 c covering from 17 K to non-supercondcuting in the overdoped region. High resolution angle resolved photoemission spectroscopy (ARPES) 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 surface are observed and quantitatively analyzed in all 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 ∼0.35. This transition coincides with the change that the sample undergoes from 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. They provide important information in understanding the connection between the disappearance of superconductivity and the Lifshitz transition in the overdoped region.

Compartmentalizing the cuprate strange metal

“…Thus, at least from a Boltzmann perspective, the marked decrease in ∆ρpHq{ρp0q with overdoping seems puzzling, though could arise from a decrease in the anisotropy of the in-plane mean-free-path as p approaches p sc . Note that any such decrease in the anisotropy of cannot be caused by the Fermi energy F moving away from a van Hove singularity (vHs) since in Bi2201, the vHs crossing point is believed to be located closer to p sc than to p ˚ [78].…”

High-Tc superconductors as a New Playground for High-order Van Hove singularities and Flat-band Physics

“…These scenarios provide a good description of the cuprates. For example, in Bi2212 T c is maximal near x cross , and → 0 near x V HS [29], where the pairing strength also vanishes [30].…”

Hole-Like Fermi Surface in the Overdoped Non-Superconducting Bi$_{1.8}$Pb$_{0.4}$Sr$_2$CuO$_{6+δ}$

“…Experimentally, the coincidental loss of superconductivity and the Lifshitz transition have been observed in some materials at the overdoped end of the superconducting dome, reviving the interest in this matter [6,[10][11][12][13].…”

“…In the case of the single Cu-O plane cuprates, the coincidence could be considered as a clear-cut evidence that the spin-fermion model is at play at the overdoped end-point of the doping range [10,12]. However, the recently established connection between the loss of superconductivity and the Lifshitz transition that was observed in the bilayer system, Bi 2 Sr 2 CaCu 2 O 8+δ (Bi2212) raises more questions [11,13].…”