Orbital and spin physics in LiNiO2 and NaNiO2

Albert J. W. Reitsma, Louis F. Feiner, Andrzej M. Oles'

We derive a spin-orbital Hamiltonian for a triangular lattice of e_g orbital degenerate (Ni^{3+}) transition metal ions interacting via 90 degree superexchange involving (O^{2-}) a…