ENERGY-LEVELS OF ONE AND 2 HOLES IN PARABOLIC QUANTUM DOTS

Calculations of energy levels of single-hole and two-hole states in a GaAs/Al0.3Ga0.7As parabolic quantum dot have been performed with a mul tiband effective-mass method. Both the valence-band degeneracy and the Coulomb interaction are taken into account using the axial approximat ion for the bulk band structure. The variational problem is solved wit h an iterative relaxation technique which allows us to use a large num ber of basis functions. The valence-band mixing is shown to be substan tial and the Coulomb interaction between the holes leads to a resonant tunneling energy that is (in general) nonlinear with respect to the s trength of the confinement potential. It is found that at sufficiently large confinement potentials, both the single-hole and two-hole groun d states are changed from primarily heavy-hole-like to light-hole-like .