New shell structures and their ground electronic states in spherical quantum dots (II) under magnetic field

We theoretically studied the electronic structure of the three-dimensional spherical parabolic quantum dot (3D-SPQD) under a magnetic field. We obtained the quantum dot orbitals (QDOs) and determined the ground state by using the extended UHF approach where the expectation values of the z component of the total orbital angular momentum (L̂_z) are conserved during (the scf-procedure. The single-electron treatment predicts that the applied magnetic field (B) creates k-th new shells at the magnetic field of B_k =k(k + 2)/(k+ 1)ω₀ with the shell-energy interval of ℏω₀(k + 1), where ω₀(= ℏ/m*l₀²) is the characteristic frequency originating from the spherical parabolic confinement potential. These shells are formed by the level crossing among multiple QDOs. The interelectron interaction breaks the simple level crossing but causes complicated dependences among the total energy, the chemical potential and their differences (magic numbers) with the magnetic field or the number of confinement electrons. The ground state having a higher spin multiplicity is theoretically predicted on the basis of the quasi-degeneracies of the QDOs around these shells.