Electronic border states in mesoscopic metallic cavities: their contribution to the orbital magnetism

We present a study of persistent currents (PC) in mesoscopic two-dimensional metallic cavities. The cavity is simulated with a gate potential that constrains the electrons to be in the regions of the sample. Varying the profile of the gate potential we can change the size and the geometry of the sample. We study non-single connected samples for which the typical current, I_typ, is substantially enhanced at half-filling, due to the existence of electronic border states near the Fermi level for this filling. These states have a large angular momentum and its response to the magnetic external flux is paramagnetic. We discuss the relevance of our results in relation to the, as yet, unexplained discrepancies between measurements of large values of PC in mesoscopic metallic rings and theoretical predictions.