Influence of varying magnetic order in external magnetic field on the electronic structure and Fermi surface within the $t$–$J$ model

We investigate the electronic structure of the two-dimensional $t$–$J$ model in a transverse external static magnetic field with canted long-range magnetic order using cluster perturbation theory. Distribution of spectral weight in the whole range of fields from zero to ferromagnetic saturation is explored. We demonstrate the possibility of a sharp change in a distribution of spectral weight at the Fermi level associated with the magnetic correlations when varying magnetic field.