Spontaneous Fermi Surface Deformation in the Three-Band Hubbard Model: A Variational Monte Carlo Study

We perform a variational Monte Carlo study of spontaneous d-waveform Fermi surface deformation (dFSD) within the three-band Hubbard model. It is found that the variational energy of a projected Fermi sea is reduced by introducing anisotropy between the hopping integrals along the x- and y-directions. Our results show that the dFSD state has the strongest tendency at half-filling in the absence of magnetism, and disappears as the hole concentration increases to nh ≈ 1.15. This is in qualitative agreement with the results of the mean field analysis and the exact diagonalization calculation for one-band models, and provides a qualitative explanation of the “intra-unit-cell” electronic nematicity revealed by scanning tunneling microscopy. An analysis of the dependences of dFSD on the parameters of the three-band model indicates that the copper on-site Coulomb interaction, nearest-neighbor copper–oxygen repulsion, and charge-transfer energy have marked positive effects on dFSD.