Electronic structure of Sm and Eu chalcogenides
Electronic structure of Sm and Eu chalcogenides
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DOI：
10.1002/pssb.200405226
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发表时间：
2004-11
期刊：
影响因子：
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通讯作者：
A. Svane;G. Santi;Z. Szotek;W. Temmerman;P. Strange;M. Horne;G. Vaitheeswaran;V. Kanchana;L. Petit;H. Winter
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文献类型：
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作者：
A. Svane;G. Santi;Z. Szotek;W. Temmerman;P. Strange;M. Horne;G. Vaitheeswaran;V. Kanchana;L. Petit;H. Winter
Sm 和 Eu 单硫族化物的基态构型是通过使用自相互作用校正的局部自旋密度近似计算总能量来确定的。除 SmO 外，Sm 硫族化物的特征是二价 f6 Sm 离子，而所有 Eu 硫族化物都具有基态二价 f7 Eu 离子。在压力下，Eu 和 Sm 硫属化物表现出向中间价态的同构转变，在总能量计算中由 Sm 离子上的局域 f5 配置（Eu 离子上的 f6）以及费米能级部分占据的 f 带表示。基本 f → d 跃迁的能量决定了半导体能隙的值，它是通过在删除一个 f 电子的超级电池方法中对带电稀土离子（Eu+ 或 Sm+）的总能量计算来确定的。压力系数与实验结果非常吻合，同构转变的发生与带隙的闭合密切相关。 （© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA，魏因海姆）
The ground state configuration of the monochalcogenides of Sm and Eu is determined from total energy calculations using the self‐interaction corrected local‐spin‐density approximation. The Sm chalcogenides, with the exception of SmO, are characterized by divalent f6 Sm ions, while all the Eu chalcogenides have divalent f7 Eu ions in the ground state. With pressure, the Eu and Sm chalcogenides exhibit isostructural transitions into an intermediate valent state, which in the total energy calculations is represented by localized f5 configurations on the Sm ions (f6 on Eu ions) together with a partly occupied f‐band at the Fermi level. The energy of the fundamental f → d transition, which determines the value of the semiconducting gap, is determined by total energy calculations of the charged rare earth ion (Eu+ or Sm+) in a supercell approach with one f‐electron removed. The pressure coefficients are in excellent agreement with experiment, and the occurrence of isostructural transitions is intimately related to the closure of the band gap. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)