Spin/orbital coupling and charge ordering in LaMnO3/SrMnO3 superlattice

Coupled spin, orbital and charge ordering in half-doped perovskite La1/2Sr1/2MnO3 (LSMO) superlattice are quantitatively investigated in realspace using the generalized gradient approximation (GGA) plus on-site Coulomb repulsion U (GGA+U) method. It is found that the high spin Mn3+ site exhibits an elongation of MnO6 octahedral for the Jahn–Teller distortion, with estimated distortion energy about 0.1 eV. The occupied eg states of Mn3+ cations are predominantly of dz2 character, which contribute mainly to the orbital ordering in LSMO. Mn3+ and Mn4+ ions show electronic disproportionation and lead to an eg charge ordering distribution. As the thickness of one period of LSMO superlattice increases, the spin magnetic moments increase and the charge order effect reduces.

► Coupled spin, orbital and charge ordering in La1/2Sr1/2MnO3 are quantitatively investigated.
► We find that the orbital ordering is predominantly introduced by Mn dz2.
► Coupled ordering gives rise to AFM order for 3434 structure and FM order for 3344 structure.
► As the thickness of one period of LSMO superlattice increases, charge order effect reduces.