Electronic Structures of Few Electrons in a Quantum Dot under Magnetic Fields

The many-body effect on the electronic structures of a few electrons confined in a quantum dot is calculated, under magnetic fields, by the exact diagonalization method. When the Coulomb interaction is comparable to the one-electron level spacings and the magnetic field is not too large, the peak positions of the Coulomb oscillation reflect a shell structure of the one-electron levels, which is in semi-quantitative agreement with experimental results [Tarucha et al. : Phys. Rev. Lett. 77 (1996) 3613]. Under strong magnetic fields, the correlation effect results in transitions of the ground state. These transitions can be observed as cusps of the magnetic-field dependence of the peak positions, in the presence of the Zeeman effect.