Electronic structure study of triangular lattices in FeGa 2 S 4 , Fe 2 Ga 2 S 5 , and NiGa 2 S 4 : Photoemission spectroscopy and Hartree-Fock calculations
Electronic structure study of triangular lattices in FeGa 2 S 4 , Fe 2 Ga 2 S 5 , and NiGa 2 S 4 : Photoemission spectroscopy and Hartree-Fock calculations
复制标题
FeGa 2 S 4 、Fe 2 Ga 2 S 5 和 NiGa 2 S 4 中三角晶格的电子结构研究：光电发射光谱和 Hartree-Fock 计算
DOI：
10.1103/physrevb.79.134422
复制
发表时间：
2009
期刊：
影响因子：
--
通讯作者：
S. Nakatsuji
中科院分区：
文献类型：
--
作者：
K. Takubo;T. Mizokawa;Y. Nambu;S. Nakatsuji
用光电子能谱方法研究了${\text{Fe}}_{2}{\text{Ga}}_{2}{\text{S}}_{5}$，和{Text{Niga}}_{2}{\Text{S}}_{4}中Fe和Ni三角晶格的电子结构。关于${\Text{FeS}}_{6}$和${\Text{NIS}}_{6}$团簇模型的组态-相互作用计算，以及关于${\Text{FES}}_{2}$和${\Text{NIS}}_{2}$三角晶格的无限制Hartree-Fock计算。对$\Text{Fe}\Text{}2p$核心能级谱的团簇模型分析表明，$\Text{S}\Text{}3p$to$\Text{Fe}\Text{}3D$电荷转移能$\Ensureath{\Delta}$是$\Ensureath{\sim}2.5\Text{}\Text{ev}${\Text{Fega}}_{2}{\Text{S}_{4}$和${\Text{Fe}}_{2}{\Text{Ga}_{2}{\Text{S}}_{5}$，与在${\Text{Niga}}_{2}{\Text{S}}_{4}$中找到的小$\EnsureMath{\Delta}$$(\EnsureMath{\sim}\EnsureMath{-}1\Text{}\Text{ev})$不同。用不受限制的Hartree-Fock计算考察了超交换路径与$EnsureMath值之间的关系。在${\Text{Fega}}_{2}{\Text{S}}_{4}$和${\text{Fe}}_{2}{\text{Ga}}_{2}{\text{S}}_{5}$，中，最近邻站点之间的超交换作用占主导地位，而第三近邻站点之间的超交换作用在${\Text{Nega}}_{2}{\Text{S}}_{4}$中增强。
We have studied the electronic structure of the Fe and Ni triangular lattices in ${\text{FeGa}}_{2}{\text{S}}_{4}$, ${\text{Fe}}_{2}{\text{Ga}}_{2}{\text{S}}_{5}$, and ${\text{NiGa}}_{2}{\text{S}}_{4}$ using photoemission spectroscopy measurements, configuration-interaction calculations on ${\text{FeS}}_{6}$ and ${\text{NiS}}_{6}$ cluster models, and unrestricted Hartree-Fock calculations on ${\text{FeS}}_{2}$ and ${\text{NiS}}_{2}$ triangular lattices. The cluster-model analysis of the $\text{Fe}\text{ }2p$ core-level spectra shows that the $\text{S}\text{ }3p$ to $\text{Fe}\text{ }3d$ charge-transfer energy $\ensuremath{\Delta}$ is $\ensuremath{\sim}2.5\text{ }\text{eV}$ in ${\text{FeGa}}_{2}{\text{S}}_{4}$ and ${\text{Fe}}_{2}{\text{Ga}}_{2}{\text{S}}_{5}$, in contrast to the small $\ensuremath{\Delta}$ $(\ensuremath{\sim}\ensuremath{-}1\text{ }\text{eV})$ found in ${\text{NiGa}}_{2}{\text{S}}_{4}$. The relationship between the $\ensuremath{\Delta}$ value and the superexchange pathway has been examined using the unrestricted Hartree-Fock calculations. In ${\text{FeGa}}_{2}{\text{S}}_{4}$ and ${\text{Fe}}_{2}{\text{Ga}}_{2}{\text{S}}_{5}$, the superexchange interaction between the nearest-neighbor sites is dominant while that between the third-nearest-neighbor sites is enhanced in ${\text{NiGa}}_{2}{\text{S}}_{4}$.