Vortex core spectroscopy links pseudogap and Lifshitz critical point in a cuprate superconductor

TL;DR

This study uses vortex-core spectroscopy to explore the relationship between the pseudogap phase and Lifshitz transition in a cuprate superconductor, revealing a doping-dependent evolution of vortex states linked to electronic phase changes.

Contribution

It provides the first direct observation of how vortex-core electronic structures evolve across the pseudogap endpoint and Lifshitz transition in a cuprate superconductor.

Findings

Vortex-core spectra change from pseudogap-like to BCS-like across doping.

The crossover occurs near the pseudogap endpoint at p* ≈ 0.21.

Vortex core states are sensitive probes of the cuprate ground state.

Abstract

Understanding how superconductivity competes with other electronic phases in cuprates requires direct access to the hidden non-superconducting low temperature phase, for which Abrikosov vortices provide a unique local probe. We map the doping- and field-dependent evolution of vortex-core states in Bi$_{2}$Sr$_{2}$CaCu$_{2}$O$_{8+\delta}$ across a broad doping range spanning the Fermi-surface Lifshitz transition. High-resolution scanning tunneling spectroscopy reveals a striking transformation of the vortex-core spectrum from unconventional, pseudogap-like signatures at moderate doping to more BCS-like behavior beyond a critical doping $p^* \approx 0.21$. This crossover aligns with the pseudogap endpoint and the onset of Fermi-surface reconstruction, indicating a direct link between pseudogap physics and vortex electronic structure. Our findings highlight the vortex core as a sensitive local probe of the cuprate ground state.