  We have investigated the electronic states of planar quantum dots at the ZnO
interface containing a few interacting electrons in an externally applied
magnetic field. In these systems, the electron-electron interaction effects are
expected to be much stronger than in traditional semiconductor quantum systems,
such as in GaAs or InAs quantum dots. In order to highlight that stronger
Coulomb effects in the ZnO quantum dots, we have compared the energy spectra
and the magnetization in this system to those of the InAs quantum dots. We have
found that in the ZnO quantum dots, the signatures of stronger Coulomb
interaction manifests in an unique ground state that has very different
properties than the corresponding ones in the InAs dot. Our results for the
magnetization also exhibits behaviors never before observed in a quantum dot:
We have found a stronger temperature dependence and other unexpected features,
such as paramagnetic-like behavior at high temperatures for a quantum-dot
helium.
