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非球对称势场与轨道有序化:NiO电子结构再研究 被引量:2

Orbital ordering and nonsphericity in potential: LDA+ U approach to the electronic structure of nickel oxide
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摘要 用含有非球对称修正的FP LMTO和LDA +UDFT,LDA +USIC研究了NiO的电子结构 ,发现由于非球对称势场的引入 ,导致了占据的 3d轨道eg 分量的轨道有序化 .结果表明在这一类复杂的强关联电子中 ,原子球内非球对称性多极势场对电子结构的影响已经比较明显 :除了上述的轨道有序化以外 ,eg 分量的位置下移 ,宽度明显变窄 ,呈现局域化的趋势 ;两种不同LDA +U方法计算得出的电荷转移能隙分别为 3 37eV(DFT)和 2 5eV(SIC) .同时发现在NiO中 ,上、下Hubbard带实际上是由占据的和非占据的 3deg 轨道构成 ,3dt2g轨道和O 2p轨道的杂化带具有较大的带宽 ,因而也具有一定的巡游特性 .结果表明在NiO中有特征明显的 3d电子轨道有序化 .通过研究得出结论 :在NiO这一类体系的电子结构计算中 ,势场的非球对称性部分和球间区势场的作用 。 In this article the LDA+ U SIC and LDA+ U DFT methods are used to calculate the electronic properties of highly correlated compound NiO. It is found that the top of the occupied states consists of mainly Ni 3d states with t 2g symmetry in the minor spin direction in LDA+ U SIC calculation. The occupied weight of e g component is located below 8 0 eV relative to the valence band edge and is also separated from the rest of the occupied valence band by a small band gap. All these findings are in good agreement with existing GW and SIC calculations for NiO. This study on NiO yields also an orbital ordering description for Ni 3d states and as a further result, leads to the conclusion that the orbital polarization and non sphericity of potential within atomic spheres have essential impacts on the electronic states in antiferromagnetic(AFM) NiO. Meanwhile, the corresponding LDA+ U DFT calculation yields a similar description with LMTO ASA study especially on the top of valence in NiO. The result suggests that the orbital polarization and the hybridization between O 2p and Ni 3d have essential impacts in describing the essential electronic properties of AFM NiO.
机构地区 浙江大学物理系
出处 《物理学报》 SCIE EI CAS CSCD 北大核心 2002年第11期2602-2605,共4页 Acta Physica Sinica
基金 国家自然科学基金 (批准号 :1 0 1 740 6 1 ) 国家教育部留学回国人员基金 (批准号 :2 0 0 0 36 7)资助的课题
关键词 非球对称势场 轨道有序化 NIO 关联电子系统 过渡金属氧化物 电子结构 氧化镍 correlated electron system, transition metal oxide, electronic structure
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