Low-frequency magnetic oscillations induced by strongly electron correlations

To explain the low frequencies of quantum oscillations observed in lightly doped cuprates, we consider the two-dimension Hubbard model supplemented with the perpendicular magnetic field. For large Hubbard repulsions, the electron spectrum is investigated using the cluster perturbation theory. Obtained frequencies of magnetic oscillations at small deviations from half-filling are close to those observed experimentally, $F\approx500$~T. They stem from small Fermi surface pockets located in the nodal regions of the Brillouin zone. The pockets are formed by Fermi arcs and less intensive segments, which make the pockets nearly circular.