DOPING-INDUCED INCOMMENSURATE ANTIFERROMAGNETISM IN A MOTT-HUBBARD INSULATOR

Properties of incommensurate spiral spin phases are calculated at the mean-field level for a single-band Hubbard Hamiltonian with variable hole density, by adapting both the Hartree-Fock decoupling and the Kotliar-Ruckenstein slave-boson approach to a regular twist of the spin quantization axes from site to site in a two-dimensional square lattice. The relative stability of the (1,1) and (1,0) spiral phases, the coexistence of the antiferromagnetic and the spiral phases over a finite range of hole density, and the stiffness of the spirals against fluctuations of their direction and pitch are discussed within the model Hamiltonian over a wide range of hole density and interaction strength.