SEMICLASSICAL STUDY OF THE MAGNETIZATION OF A QUANTUM-DOT

The magnetization of a quantum dot at zero temperature is examined wit hin the semiclassical periodic orbit theory. Using two limits of the e ffective single-particle potential-a harmonic oscillator and a circula r infinite-well potential (disc billiard)-we study the shell structure in the magnetization that oscillates as a function of the magnetic fi eld around its average value given by the Landau susceptibility. For h armonic confinement, we apply for arbitrary field strength the Gutzwil ler trace formula for isolated orbits. For disc confinement, a recentl y derived trace formula for arbitrarily strong magnetic fields (Blasch ke and Brack, 1997; Blaschke, 1995) is employed. For both types of con finement, the ''supershell'' structure in the weak-held regime can be explained by the interference of the shortest periodic orbits. The Aha ronov-Bohm oscillations in the strong-field regime are governed by the orbit that goes along the edge of the system. (C) 1998 Academic Press .