First principles investigation of half-metallicity and spin gapless semiconductor in CH_3NH_3Cr_xPb_(1-x)l_3 mixed perovskites

摘要

AbstractThe structural, electronic and magnetic properties of organic–inorganic hybrid mixed perovskites CH3NH3CrxPb1−xI3(x = 0.25, 0.50, 0.75, 1.00) in cubic, tetragonal and orthorhombic phases have been investigated by first-principles calculation. The results indicate that the tetragonal CH3NH3Cr0.75Pb0.25I3is a spin gapless semiconductor with Curie temperature of 663 K estimated using mean field approximation. All other CH3NH3CrxPb1−xI3mixed perovskites are half-metallic ferromagnets together with 100% spin polarization, and their total magnetic moment are 4.00, 8.00, 12.00 and 16.00 µBper unit cell forx = 0.25, 0.50, 0.75 and 1.00, respectively. The effect of <100>, <110> and <111> orientation of organic cation CH3NH3+on the electronic properties of CH3NH3Cr0.50Pb0.50I3was investigated. The results show that the CH3NH3+in different orientations have a slight effect on the lattice constants, the energy gap in minority-spin states, half-metallic gap, local magnetic moment, and Curie temperature.