Anomalous diamagnetic behavior of a confined two-dimensional electron within an external magnetic field

An anomalous diamagnetic behavior of a confined two-dimensional electron wi thin an external magnetic field (perpendicular to the confining plane) is d iscussed in this letter. Although this finding is consistent with the pione ering work of Robnik, it has not been previously reported. When this effect occurs, the ratio between the typical length of spatial and magnetic confi nement is an integer number. This property leads also to a quantization of the magnetic flux across the confining circle. The possible consequences of the peculiar behavior of the electron within such a structure are discusse d.