Electrostatics of Vortices in Type-II Superconductors

Abstract

In a type-II superconductor the gap variation in the core of a vortex line induces a local charge modulation. Accounting for metallic screening, we determine the line charge of individual vortices and calculate the electric field distribution in the half space above a field penetrated superconductor. The resulting field is that of an atomic size dipole $\mathbf{d}\ensuremath{\sim}{\mathrm{ea}}_{B}\stackrel{^}{z}$, ${a}_{B}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}{\ensuremath{\Elzxh}}^{2}/{\mathrm{me}}^{2}$ is the Bohr radius, acting on a force microscope in the pico- to femto-Newton range.