Electronic Hamiltonian and antiferromagnetic interactions in La2CuO4

URL:http://link.aps.org/doi/10.1103/PhysRevB.40.2620 DOI:10.1103/PhysRevB.40.2620A many-body Hamiltonian for La2CuO4 with ab initio parameters is solved numerically using embedded-cluster approximations. The results give an antiferromagnetic insulator with a 2-3 eV energy gap, consistent with spectroscopic measurements, NMR chemical shifts, and the spin-wave velocity. The Néel state has a significant frustration due to second-neighbor interactions, J2/J1≊5%-8%. Two competing states are found for holes introduced by doping, with primarily in-plane oxygen pσ and out-of-plane oxygen pz character.This work was supported by National Science Foundation Grant No. NSF-DMR86-12860