Effect of electron-electron interactions on the magnetization of quantum dots

The low-temperature magnetization of parabolic quantum dots is calculated and is shown to be a sensitive probe of interaction effects. The interaction causes the ground state to occur at certain magic values of the total angular momentum, the strength of the magnetic field determining which of them is selected. Increasing the mangetic field causes the ground-state angular momentum to jump from one magic value to another and this causes the discontinuities in the magnetization. The effects of spin lead to extra discontinuities at low magnetic field. The magic angular momenta for the spin-polarized case are derived by a simple physical argument.