Reconstruction of the Fermi surface of HTSC cuprates in a high magnetic field

The effect of a high magnetic field on the electronic structure of HTSC cuprates is considered. The study is performed in the t-t′-t″-J* model, and the high magnetic field effect is taken into account not only as the Zeeman splitting of the one-electron levels, but also in the occupation numbers of the states with different spin projections and in the formation of the spin correlation functions. The field is assumed to be high enough to align all of the spins along the field. As a result, the Fermi surface reconstruction is obtained from four hole pockets about the nodal point (π/2, π/2) in the paramagnetic phase to a large hole pocket about the point (π, π) in the ferromagnetic phase. As the magnetic field strength decreases, a number of quantum phase transitions are revealed; they are manifested in the changed Fermi surface topology. The Fermi surface reconstruction with a decreasing field is qualitatively the same as that with an increasing doping degree in the absence of a magnetic field.