# Vertical temperature-boundary of the pseudogap under the superconducting dome of the Bi2Sr2CaCu2O8+d phase-diagram

## TL;DR

This study combines experiments and theory to identify a vertical boundary of the pseudogap in the phase diagram of Bi2Sr2CaCu2O8+d, revealing its disappearance at a specific doping level across all temperatures within the superconducting dome.

## Contribution

It provides evidence that the pseudogap boundary is vertical in the phase diagram, linking the pseudogap collapse to a Lifshitz transition in Bi2Sr2CaCu2O8+d.

## Key findings

- Pseudogap disappears at doping pc between 0.222 and 0.226.
- The normal-state pseudogap collapses at a Lifshitz transition.
- The pseudogap boundary forms a vertical line in the T-p phase diagram.

## Abstract

Combining electronic Raman scattering experiments with cellular dynamical mean field theory, we present evidence of the pseudogap in the superconducting state of various hole-doped cuprates. In Bi2Sr2CaCu2O8+d we track the superconducting pseudogap hallmark, a peak-dip feature, as a function of temperature T and doping p, well beyond the optimal one. We show that, at all temperatures under the superconducting dome, the pseudogap disappears at the doping pc, between 0.222 and 0.226, where also the normal-state pseudogap collapses at a Lifshitz transition. This demonstrates that the superconducting pseudogap boundary forms a vertical line in the T-p phase diagram.