Electronic and structural anomalies in lead chalcogenides
Electronic and structural anomalies in lead chalcogenides
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DOI：
10.1103/physrevb.55.13605
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发表时间：
1997-05-15
影响因子：
3.7
通讯作者：
Zunger, A
中科院分区：
文献类型：
--
作者：
Wei, SH;Zunger, A
岩盐结构PbS、PbSe和PbTe半导体及其合金表现出一系列相对于II-VI系的电子结构异常，包括L点直接能隙的出现、带隙和价带最大能量与阴离子的异常顺序、负光学弯曲和负带隙压力系数。我们发现，这些异常的结果从下面的价带顶的Pb s带的发生，设置耦合和水平排斥在L点。此外，我们发现，挫折八面体结构的拓扑结构导致发生在随机合金中的两个不同的债券为每个阴离子-阳离子对和预测的稳定的散装有序Pb 2STe铜铂类相。
The rocksalt-structure PbS, PbSe, and PbTe semiconductors and their alloys exhibit a series of electronic structure anomalies relative to the II-VI system, including the occurrence of direct gaps at the L point, anomalous order of band gaps and valence-band maximum energies versus anions, negative optical bowing, and negative band-gap pressure coefficients. We show that these anomalies result from the occurrence of the Pb s band below the top of the valence band, setting up coupling and level repulsion at the L point. Furthermore, we find that the topology of the frustrated octahedral structure leads to the occurrence in the random alloy of two distinct bonds for each anion-cation pair and to the predicted stabilization of bulk ordered Pb2STe CuPt-like phase.