Effective transfer integrals for the Jahn-Teller distortion in LaMnO3

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