Wang-MacDonald d-wave vortex cores observed in heavily overdoped Bi$_2$Sr$_2$CaCu$_2$O$_{8+\delta}$

TL;DR

This study uses scanning tunneling spectroscopy to reveal the d-wave electronic structure of vortices in heavily overdoped Bi2212, showing a zero-bias conductance peak that splits with distance, clarifying previous conflicting observations.

Contribution

It demonstrates the intrinsic d-wave vortex core structure in heavily overdoped Bi2212 and explains prior discrepancies caused by vortex-vortex interactions.

Findings

Observation of a zero-bias conductance peak at the vortex center.

Splitting of the conductance peak with increasing distance from the core.

Previous unconventional structures are due to vortex-vortex interactions.

Abstract

Low magnetic field scanning tunneling spectroscopy of individual Abrikosov vortices in heavily overdoped Bi$_2$Sr$_2$CaCu$_2$O$_{8+\delta}$ unveils a clear d-wave electronic structure of the vortex core, with a zero-bias conductance peak at the vortex center that splits with increasing distance from the core. We show that previously reported unconventional electronic structures, including the low energy checkerboard charge order in the vortex halo and the absence of a zero-bias conductance peak at the vortex center, are direct consequences of short inter-vortex distance and consequent vortex-vortex interactions prevailing in earlier experiments.