  The intra-unit-cell nematic phase is studied within the three-band Emery
model of the cuprates with the use of the approach based on the diagrammatic
expansion of the Gutzwiller wave function (DE-GWF). According to our analysis
the spontaneous $C_4$ symmetry breaking of the electronic wave function,
leading to the nematic behavior, can appear due to electron correlations
induced mainly by the onsite Coulomb repulsion, even in the absence of the
corresponding intersite oxygen-oxygen repulsion term. The latter has been
considered as the triggering factor of the nematic state formation in a number
of previous studies. Also, we show that, at the transition to the nematic phase
electron concentration transfer from $d$- to $p$- orbitals takes place, apart
from the usually discussed $p_x/p_y$ polarization. The determined stability
regime of the nematic phase appears in the doping range similar to that of the
paired phase, showing that both phases have a common origin, even though they
compete. Also, we show that in a significant doping range a coexistence region
of superconductivity and nematicity appears. The results are discussed in the
view of the experimental findings considering the relation between nematicity
and pseudogap behavior.
