NONLINEAR ORBITAL MAGNETIC RESPONSE IN ISOLATED QUANTUM DOTS

The magnetic response of an ensemble of quantum dots all having the sa me macroscopic parameters but different defect configurations is calcu lated. The number of electrons in each dot is constant. The response i s paramagnetic, can be large at small fields for two-dimensional (2D) dots, and has a characteristic nonlinear behavior including a regime w here the magnetization is field independent in 2D, albeit with signifi cant corrections. These results are due to the crossover in the spectr al correlations brought about by the time-reversal symmetry breaking d ue to the magnetic field.