Spectrum structure for a three-dimensional periodic array of quantum   dots in a uniform magnetic field
  By means of the operator extension theory, we construct an explicitly solvable model of a simple-cubic three-dimensional regimented array of quantum dots in the presence of a uniform magnetic field. The spectral properties of the model are studied. It is proved that for each magnetic flux the band is the image of the spectrum of the tight-binding operator under an analytical transformation. In the case of rational magnetic flux the spectrum is described analytically. The flux-energy and angle-energy diagrams are obtained numerically. 
J.Bruening, V.V.Demidov, V.A.Geyler, A.V.Popov