Quantum dots created through spherically polarized nuclear spins

Electronic structure of quantum dots created by spherically polarized nuclear spins is studied. A peculiarity of this type of quantum dots is that their energy spectrum evolves as a result of nuclear spin diffusion and relaxation. We have found that the number of energy levels, as well as their depth, decreases with time in quantum dots with spherical nuclear spin polarization. This observation contrasts with previous results obtained for quantum dots with cylindrical nuclear spin polarization.