钙钛矿型HoNiO3中电荷歧化的第一原理研究

应用第一原理的密度泛函方法,研究钙钛矿型过渡金属氧化物HoNiO_3的电子结构. HoNiO_3在正交结构（空间群为Pbnm）和单斜结构（空间群为P2_1/n）的电子密度图表明Ni在正交相中只存在Ni^３＋一种组态，而在单斜相中则存在Ni^(3-δ)+和Ni^(3+δ) +两种不同的组态. 电荷歧化特征值δ可由Ni3d电子态密度中非键t_2g部 分反映. 通过t_2g态密度在正交和单斜相的相对变化，可以算得δ 值为0.34±0.01. 关键词： HoNiO＿3 电荷歧化 电子结构 第一原理计算

First-principles investigation of charge disproportionation in HoNiO3 perovskite

We have investigated the electronic structure of HoNiO_3 perovskit e using first principles based on the density_functional theory. A comparison of elec tron_density map between orthorhombic and monoclinic structures indicated that there is only one type of Ni^3+state in the orthorhombic_metallic phase (space group Pbnm), and there are two types of Ni^(3-δ)+ and Ni^(3+δ) + states in the monoclinic_insulating phase ( space group P2_1/n). The characteristic parameter of charge di sproportionation δis concerned with the non_bonding t_2g band of partial density of states of Ni3d electron. δis calculated to be 0. 34±0.01， based on the changes of t_2gband from orthorhombic to monoclinic phase.