Electron states in a magnetic quantum ring

Electron states in a magnetic quantum ring are investigated. The electron i s assumed to be confined to a plane in the presence of a magnetic field whi ch is zero within the ring a < r < b and has a constant value B-0 outside i t. In this way, the perturbation caused by this field distribution is found to be quite different from that corresponding to a magnetic quantum disk, as regards electron states and circulating currents. in the case of electro n stares, the main effect is the splitting of the corresponding Landau leve ls into a sort of quasi-miniband around them and modulated by the inner rad ius. It is also found that probability current can change its direction dep ending on the missing Bur quanta, a mechanism mat is also governed by the s ize of the inner radius. Moreover, when the inner radius approaches zero, t he results for a magnetic quantum disk are recovered, as expected.