摘要:
基于密度泛函理论结合投影缀加平面波方法,通过VASP软件包执行计算,在分别考虑电子自旋阻挫共线与非共线的磁性结构基础上,研究了正交结构下多铁性DyMnO3材料在不同磁性构型下的晶格参数、总能、磁性、电子态密度和能带结构.计算过程中选取广义梯度近似赝势,同时使用局域自旋密度近似+U 方法处理强关联作用下3d电子的计算结果.计算结果表明：Mn离子为A型反铁磁态磁性构型的情况下能量最低结构最为稳定, Dy稀土离子磁性甚微,可忽略不计；当考虑电子自旋为非共线排列时,正交DyMnO3的总能提高、磁矩增大；从电子结构图分析可知,材料为间接能隙绝缘体,能隙宽度约为0.38 eV,加U 后为1.36 eV,导致晶格畸变的主要原因为Mn-3d与O-2p电子之间强烈的杂化作用.
Abstract:
The lattice parameters, total energy, magnetism, density of states, and band structure in the multiferroic material DyMnO3 with orthorhombic structure are investigated by using different magnetic models, and the non-collinear magnetism and the collinear mag-netism are taken into account by using density functional theory combined with the projector augmented wave method via the software package of VASP. The generalized-gradient approximation (GGA) pseudo potential is used in the calculation, and the local spin density approximation+U method is also adopted to deal with the strong correlation effect of the 3d electrons. The results show that Mn ion in the AAFM magnetic model has the lowest energy and is the most stable, while the weak magnetism of the rare earth ion Dy can be neglected, and that the total energy and the magnetic moment of DyMnO3 in orthorhombic structure increase when the non-collinear magnetic structure of Mn ion is considered and that the DyMnO3 material is an indirect-gap insulator with an energy gap value of 0. 38 eV obtained from GGA or 1.36 eV from GGA+U , and the lattice distortion should be considered to be due to the hybridization between Mn-3d and O-2p electrons, which can be analyzed from the density of state.
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