Nb掺杂导致LaMnO_3绝缘体-金属转变的第一性原理研究

采用基于密度泛函理论(DFT)的第一性原理计算,系统研究了Nb掺杂LaMn_(1-x)Nb_xO_3(x=0,0. 25,0. 5,0. 75)的结构和电磁性质.计算结果表明,所有的LaMn_(1-x)Nb_xO_3都稳定在正交结构. LaMn_(1-x)Nb_xO_3当x 0. 5时为A型反铁磁绝缘体,在x=0. 5和0. 75时为G型反铁磁金属.随着Nb掺杂量增加,当x=0. 5时掺杂电子占据导带的底部,系统产生绝缘体-金属转变.这意味着LaMn_(1-x)Nb_xO_3在电子器件上可能有重要的应用.另外,LaMn_(1-x)Nb_xO_3在x=0. 25和0. 75时出现了自旋玻璃行为.

First-principal investigation on insulator-metal transition in LaMnO3 induced by Nb doping

First-principle calculations were performed on the structural, electronic and magnetic properties of Nb-doped LaMn1-xNbxO3 (x = 0, 0.25, 0.5, 0.75) based on density functional theory. The calculation results show that the entire series of LaMn1-xNbxO3 stabilize in the orthorhombic structure. LaMn1-xNbxO3 is an A-type antiferromagnetic insulator at x < 0.5 and G-type antiferromagnetic metal at x = 0.5 and 0.75. As x increases, the doped electrons occupy the bottom of conduction bands at x = 0.5 so that an insulator-metal transition occurs in the system, which implies that LaMn1-xNbxO3 can have an important application in electronic devices. Furthermore, LaMn1-xNbxO3 shows spin-glass behavior at x = 0.25 and 0.75.