Electronic structure, magnetism properties and optical absorption of organometal halide perovskite CH_3NH_3XI_3 (X = Fe, Mn)

摘要

The electronic structure, magnetism properties and optical absorption of organometal halide perovskite CH~(3)NH~(3)XI~(3)(X = Fe, Mn) are studied using the first principles calculations by the generalized gradient approximation (GGA) and the GGA +  U method, respectively. The magnetic ground states of CH~(3)NH~(3)MnI~(3)and CH~(3)NH~(3)FeI~(3)are both the G-type antiferromagnetic (AFM) order. With the introduction of on-site Coulomb interactions U , CH~(3)NH~(3)FeI~(3)shows the semiconducting phase from original metallic state predicted by the GGA method. The band gap value of CH~(3)NH~(3)MnI~(3)with the G-AFM state is 1.68 eV, while the band gap in the spin majority channel is 0.694 eV and the band gap in the spin minority channel is 2.147 eV when system is in FM state. For CH~(3)NH~(3)FeI~(3)system, the band gap is 0.957 eV when system is in G-AFM state, while the band gap in the spin majority channel is 0.602 eV and the band gap in the spin minority channel is 1.215 eV when system is in FM state, which shows that photo-excited electrons of CH~(3)NH~(3)MnI~(3)and CH~(3)NH~(3)FeI~(3)with FM state will rapidly melt the local magnetic order. Furthermore, the optical properties of CH~(3)NH~(3)MnI~(3)and CH~(3)NH~(3)FeI~(3)are calculated. CH~(3)NH~(3)MnI~(3)with the FM state shows strong infrared light absorption. CH~(3)NH~(3)FeI~(3)with FM state have stronger infrared absorption than that in G-AFM state.