Electronic structure and magnetism in La2NiO4

Abstract

Self-consistent spin-polarised electronic band structure calculations have been performed for La2NiO4 in its nonmagnetic, ferromagnetic and antiferromagnetic states. The principal results are: the band structure of nonmagnetic tetragonal La2NiO4 is similar to the isostructural La2CuO4, but with two Ni-O (3d(x2-y2)-2px,y and 3d(z2)-2(pz)) anti-bonding bands and also a higher density of states at the Fermi level the ground state is found to be an antiferromagnet with a spin moment of about 0.8 mu B/Ni; no ferromagnetic solution is obtained for lattice constants within 5% of the experimental value. The electronic properties of the La2NiO4 compounds and the nature of the tetragonal-orthorhombic phase transition in both La2CuO4 and La2NiO4 are discussed in view of the present results.