CH_(3)NH_(3)PbI_(3)和CH_(3)NH_(3)MnI_(3)的电子结构和光学性质研究

Study on Electronic Structure and Optical Property of CHNHXI(X=Pb,Mn)

采用第一性原理计算,研究了有机金属卤化物钙钛矿CH_(3)NH_(3)PbI_(3)和CH_(3)NH_(3)MnI_(3)的电子结构、磁性和光吸收。CH_(3)NH_(3)PbI_(3)和CH_(3)NH_(3)MnI_(3)都是具有直接带隙半导体,CH_(3)NH_(3)MnI_(3)磁基态为G型反铁磁序(G-AFM)。CH_(3)NH_(3)MnI_(3)在G-AFM状态下的带隙值为1.668 eV;当系统处于FM态时,多数自旋通道的带隙为0.696 eV,少数自旋通道的带隙为2.148 eV。结果表明,具有FM态的CH_(3)NH_(3)MnI_(3)的光激发电子将迅速熔化局域磁序。最后计算了CH_(3)NH_(3)PbI_(3)和CH_(3)NH_(3)MnI_(3)的光学特性,结果表明具有铁磁态的CH_(3)NH_(3)MnI_(3)(FM)表现出较强的红外光吸收。

Using the first principles calculations,the electronic structure and optical absorption of the organometal halide perovskite CH_(3)NH_(3)PbI_(3)and CH_(3)NH_(3)MnI_(3)are studied.CH_(3)NH_(3)PbI_(3)and CH_(3)NH_(3)MnI_(3)are both semiconductors with direct band gap.The magnetic ground states of CH_(3)NH_(3)MnI_(3)are the G-type antiferromagnetic order(AFM).The band gap of the CH_(3)NH_(3)MnI_(3)(GAFM)is about 1.668 eV.For CH_(3)NH_(3)MnI_(3)(FM),the band gap value of the CH_(3)NH_(3)MnI_(3)(FM)in the spin majority channel is about 0.696 eV,and the band gap in the spin minority channel is about2.148 eV,which proves that photo-excited electrons of CH_(3)NH_(3)MnI_(3)(FM)will rapidly melt the local magnetic order.Finally,the optical properties of CH_(3)NH_(3)PbI_(3)and CH_(3)NH_(3)MnI_(3)are calculated,and the results show that the CH_(3)NH_(3)MnI_(3)(FM)has strong infrared light absorption.