Electrostatics of Vortices in Type-II Superconductors

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 $\mathbf{d}\sim {\mathrm{ea}}_B\hat{z}$, $a_B={ħ}^2/{\mathrm{me}}^2$ is the Bohr radius, acting on a force microscope in the pico- to femto-Newton range.