New type of charged defect in amorphous chalcogenides.
New type of charged defect in amorphous chalcogenides.
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非晶硫族化物中的新型带电缺陷。
DOI：
10.1103/physrevlett.94.086401
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发表时间：
2004
影响因子：
8.6
通讯作者：
S. Elliott
中科院分区：
文献类型：
--
作者：
S. Simdyankin;T. Niehaus;G. Natarajan;T. Frauenheim;S. Elliott
我们报告了一系列无定形硫化砷模型的密度泛函紧束缚模拟。除了先前提出的硫系玻璃中存在的带电配位缺陷外，在几种模型中还发现了一种新的缺陷对[As（4）]（-）-[S（3）]（+），由一个四配位的砷位和一个三配位的硫位组成，其中砷位为跷跷板构型，硫位为近平面三角构型。在HOMO到LUMO电子激发下，[S（3）]（+）-S-1转变为[As（4）]（-）-[S（3）]（+）对。这种结构转变伴随着HOMO-LUMO带隙尺寸的减小，这表明这种转变可能有助于这些材料中的光暗化。
We report on density-functional-based tight-binding simulations of a series of amorphous arsenic sulfide models. In addition to the charged coordination defects previously proposed to exist in chalcogenide glasses, a novel defect pair, [As(4)](-)-[S(3)](+), consisting of a fourfold coordinated arsenic site in a seesaw configuration and a threefold coordinated sulfur site in a near-planar trigonal configuration, was found in several models. The valence-alternation pairs [S(3)](+)-S-1 are converted into [As(4)](-)-[S(3)](+) pairs under HOMO-to-LUMO electronic excitation. This structural transformation is accompanied by a decrease in the size of the HOMO-LUMO band gap, which suggests that such transformations could contribute to photodarkening in these materials.