Magnetic-field effects on one- and two-hole states in parabolic quantum dots

Using a multiband effective-mass theory, we have calculated the one- and two-hole energies in a parabolic quantum dot in the presence of a perpendicular magnetic field. The valence-band degeneracy, the Coulomb interaction, and the effect of finite offsets are all taken into account. The energies are calculated variationally with an iterative relaxation technique. The single-hole levels show strong anticrossings due to the valence-band mixing. As a result they have in general a weaker field dependence compared with the corresponding uncoupled levels. For the two-hole states both the valence-band mixing and the Coulomb interaction are shown to be substantial. The correlations between the holes are strong enough to change the total angular momentum of the ground state when the magnetic field is increased.