Nonresonant inelastic x-ray scattering and energy-resolved Wannier function investigation of d-d excitations in NiO and CoO
Nonresonant inelastic x-ray scattering and energy-resolved Wannier function investigation of d-d excitations in NiO and CoO
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DOI：
10.1103/physrevlett.99.026401
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发表时间：
2007-07-13
影响因子：
8.6
通讯作者：
Finkelstein, K. D.
中科院分区：
文献类型：
--
作者：
Larson, B. C.;Ku, Wei;Finkelstein, K. D.
NiO和CoO的非共振非弹性X射线散射测量表明，在大的波矢下，Mott间隙内出现了强的偶极禁戒d-d激发。这些主要的激发是高度各向异性的，并且对于NiO具有[001]节点方向。基于一种新的，能量分辨的Wannier函数（局部密度近似+ Hubbard U）的理论分析表明，各向异性反映了局部激子波函数和局部点群对称性。粒子-空穴波函数对弱对称性破缺的敏感性表明了它在强关联系统中的广泛应用。
Nonresonant inelastic x-ray scattering measurements on NiO and CoO show that strong dipole-forbidden d-d excitations appear within the Mott gap at large wave vectors. These dominant excitations are highly anisotropic, and have [001] nodal directions for NiO. Theoretical analyses based on a novel, energy-resolved Wannier function (within the local density approximation + Hubbard U) show that the anisotropy reflects the local exciton wave functions and local point-group symmetry. The sensitivity to weak symmetry breaking in particle-hole wave functions suggests a wide application to strongly correlated systems.