Electronic structure of Humble defects in Ge and Ge0.8Si0.2
Electronic structure of Humble defects in Ge and Ge0.8Si0.2
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Ge和Ge0.8Si0.2中微缺陷的电子结构
DOI：
10.1103/physrevb.106.155302
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发表时间：
2022
影响因子：
3.7
通讯作者：
Vanderbilt, David
中科院分区：
文献类型：
--
作者：
Ren, Shang;Yang, Hongbin;Singh, Sobhit;Batson, Philip E.;Garfunkel, Eric L.;Vanderbilt, David
已知族iv型金刚石结构元素具有多种平面缺陷，包括C和{001}中的{001}平面缺陷，Si和Ge中的{111}和{113}平面缺陷。在{001}平面缺陷中，已知在Ge中存在一段时间的Humble缺陷最近也在Si-Ge合金中被观察到，但其电子结构的细节仍然知之甚少。本文采用第一性原理密度泛函计算方法研究了Ge和。我们还测量了缺陷处和远离缺陷的块状区域的硅边电子能量损失谱，并与第一性原理计算中相应硅位的理论计算进行了比较。我们发现，在理论中包含核孔效应对于再现观测到的边缘光谱是必不可少的，一旦包含了它们，结果就为不同类型的局部原子键环境提供了一组指纹。我们的第一性原理计算表明，Humble缺陷具有扩大电子带隙的趋势，这可能在带工程中具有潜在的用途。本文还讨论了在这些系统中使用混合泛函来改进带隙的描述。
The group-IV diamond-structure elements are known to host a variety of planar defects, including {001} planar defects in C and {001}, {111}, and {113} planar defects in Si and Ge. Among the {001} planar defects, the Humble defect, known for some time to occur in Ge, has recently also been observed in Si-Ge alloys, but the details of its electronic structure remain poorly understood. Here we perform first-principles density-functional calculations to study Humble defects in both Ge and. We also measure the Si-edge electron energy-loss spectra both at the defect and in a bulk-like region far from the defect and compare with theoretical calculations on corresponding Si sites in our first-principles calculations. We find that inclusion of core-hole effects in the theory is essential for reproducing the observededge spectra, and that once they are included, the results provide a set of fingerprints for different types of local atomic bonding environments in. Our first-principles calculations reveal that the Humble defects have a tendency to enlarge the electronic band gap, which may have potential uses in band engineering. The use of hybrid functionals for an improved description of the band gap in these systems is also discussed.