Charge Induced Vortex Lattice Instability

TL;DR

This paper demonstrates that vortex lattice in high-temperature superconductors becomes unstable at high magnetic fields due to charge trapped in vortex cores, supported by NMR measurements indicating electrostatic effects.

Contribution

It provides experimental evidence of vortex lattice instability caused by charge trapping, with quantitative estimates of vortex charge in Bi-2212 superconductors.

Findings

Vortex lattice becomes unstable at high magnetic fields due to charge effects.

NMR measurements indicate vortex charge of approximately 2x10^{-3} e.

Charge-induced lattice reconstruction observed in Bi-2212 superconductors.

Abstract

It has been predicted that superconducting vortices should be electrically charged and that this effect is particularly enhanced for, high temperature superconductors.\cite{kho95,bla96} Hall effect\cite{hag91} and nuclear magnetic resonance (NMR) experiments\cite{kum01} suggest the existence of vortex charging, but the effects are small and the interpretation controversial. Here we show that the Abrikosov vortex lattice, characteristic of the mixed state of superconductors, will become unstable at sufficiently high magnetic field if there is charge trapped on the vortex core. Our NMR measurements of the magnetic fields generated by vortices in Bi$_{2}$Sr$_{2}$CaCu$_{2}$O$_{8+y}$ single crystals\cite{che07} provide evidence for an electrostatically driven vortex lattice reconstruction with the magnitude of charge on each vortex pancake of $\mathbf{\sim 2}$x$\mathbf{10^{-3} e}$, depending on doping, in line with theoretical estimates.\cite{kho95,kna05}