Charge distributions due to paramagnetism and diamagnetism in thin mesoscopic superconducting rings

The charge distribution in a thin mesoscopic superconducting ring is investigated by the phenomenological Ginzburg-Landau theory. Considering a ring in a giant vortex state, we find that the charge near the inner radius may change its sign from negative to positive with increasing the applied field. It is also found that the charge distributions are due to the competition between the paramagnetic Meissner effect and the diamagnetic Meissner effect.