Electronic structure of the perovskite oxides La1−xSrxMnO3

The electronic structures of perovskite oxides La1−xSrxMnO3 are studied with local spin-density approximation (LSDA). Results show that the lowest energy is obtained when the MnO bond length is 1.95 Å with ideal cubic crystal structure. This value of MnO bond length is consistent with the experimental data. Considering a proper tetragonal distortion of the crystal, the total energy of system becomes lower. A half-metal state can be got both for the undistorted structure (MnO bond lengths are 1.95–2.10 Å) and the distorted structure. It is suggested that the effect of Jahn–Teller distortion is not the main reason of formation of half-metal state. However, the electronic properties are very sensitive to the c/ac/a ratio. Along with the increase of c/ac/a ratio, system transforms from metal to half metal and further the insulator.