Effective transfer integrals for the Jahn-Teller distortion in LaMnO3

The effective transfer integrals between two Mn sites in LaMnO3 were investigated all through the possible lattice distortions resulting from the Jahn-Teller effect. The first-principles discrete variational approach is performed to calculate the effective transfer integrals, which are basically involved in exchange interactions. The variations of Mn-O bond length predominates over the change of transfer integrals when comparing with the variations of Mn-O-Mn bond angle. The calculation suggested that the effective transfer integrals between t(2g) orbitals should also be included in exchange terms. Thus reasonable superexchange energies of interlayer or intralayer are obtained to successfully reproduce the antiferromagnetic phase in LaMnO3. [SO163-1829(99)08141-2].