Abstract
Using Monte Carlo techniques, we study a three-orbital CuO2 spin-fermion model for copper-based high-critical-temperature superconductors that captures the charge-transfer properties of these compounds. Our studies reveal the presence of spin order in the parent compound and, more importantly, stripe spin and charge order under hole doping. Due to the p−d orbital hybridization, the added holes are approximately equally distributed among the two p orbitals of the oxygen atoms and the d orbital of the copper atoms in the unit cell. In rectangular clusters of dimension 16×4 half-filled stripes are observed upon hole doping; namely, when Nh=2n holes are introduced in the system, then n vertical stripes of length 4 along the short periodic direction are formed. The original antiferromagnetic order observed in the parent compound develops a π shift across each stripe, and the magnetic structure factor has a peak at wave vector k=(π−δ,π) with δ=2πNh/N=πNh/2L, where L=16. The electronic charge is also modulated, and the charge structure factor is maximized at k=(2δ,0). As electrons are removed from the system, intracell orbital nematicity with ⟨npx⟩−⟨npy⟩≠0 develops in the oxygen sector, as well as intercell magnetic nematicity with ⟨Szi,d(Szi+x,d−Szi+y,d)⟩≠0 in the spin copper sector, in the standard notation. This occurs not only in rectangular but also in square 8×8 lattices. Our results suggest that the essence of the stripe spin and charge distribution experimentally observed in hole-doped cuprates is captured by unbiased Monte Carlo studies of a simple hole-doped charge-transfer insulator CuO2 spin-fermion model.
