# Disappearance of Superconductivity and a Concomitant Lifshitz Transition in Heavily-Overdoped Bi2Sr2CuO6 Superconductor Revealed by Angle-Resolved Photoemission Spectroscopy

## TL;DR

This study uses ARPES to reveal a Lifshitz transition from hole-like to electron-like Fermi surface in heavily overdoped Bi2Sr2CuO6, coinciding with the loss of superconductivity, thus linking Fermi surface topology changes to superconducting suppression.

## Contribution

It provides direct experimental evidence of a Lifshitz transition in heavily overdoped cuprate superconductors and connects Fermi surface topology change with the disappearance of superconductivity.

## Key findings

- Lifshitz transition occurs at doping level ~0.35.
- Fermi surface changes from hole-like to electron-like.
- Superconductivity vanishes as Fermi surface undergoes transition.

## Abstract

By partially doping Pb to effectively suppress the superstructure in single-layered cuprate Bi2Sr2CuO6+{\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 Tc 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.