Four-fold structure of vortex core states in Bi2Sr2CaCu2O8 (Bi2212)

TL;DR

This study reveals a four-fold symmetric, energy-independent modulation of the local density of states in the vortex cores of Bi2Sr2CaCu2O8, linking vortex core states to the superconducting gap and local electronic structure.

Contribution

It provides the first detailed observation of four-fold symmetric vortex core modulations in Bi2212 and connects these modulations to the vortex core states and superconducting gap.

Findings

Four-fold symmetric modulation of local density of states observed

Vortex core states located at ~6 meV

Modulation period is energy-independent

Abstract

We present a detailed study of vortex core spectroscopy in slightly overdoped Bi2Sr2CaCu2O8 using a low temperature scanning tunneling microscope. Inside the vortex core we observe a four-fold symmetric modulation of the local density of states with an energy-independent period of (4.3\pm 0.3)a0. Furthermore we demonstrate that this square modulation is related to the vortex core states which are located at ~6 meV. Since the core-state energy is proportional to the superconducting gap magnitude, our results strongly suggest the existence of a direct relation between the superconducting state and the local electronic modulations in the vortex core.