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The electronic structures and magnetic properties of layered perovskite LaSrMnO4 and Ca2RuO4 have been determined using the full-potential linearized augmented-plane-wave method within the local spin-density approximation (LSDA) and the LDA + U approach (LDA standing for local density approximation). The results of LSDA and LDA + U total-energy calculations show that the antiferromagnetic state of these materials is stable compared with the ferromagnetic and paramagnetic states. The LDA + U calculation results show that Jahn–Teller distortion of Mn–O and Ru–O octahedra produces an energy gap, and 3z2 − r2 and xy orbital ordering for LaSrMnO4 and Ca2RuO4, respectively. However, the LSDA calculation is not sufficient for describing the orbital ordering and fails to produce the band gap. The Jahn–Teller distortion stabilizes a two-dimensional planar antiferromagnetic state.

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