Dependency of a localized phonon mode intensity on compositional cluster size in SiGe alloys
Dependency of a localized phonon mode intensity on compositional cluster size in SiGe alloys
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DOI：
10.1063/5.0055307
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发表时间：
2021-07
期刊：
影响因子：
1.6
通讯作者：
S. Chung;M. Tomita;Junya Takizawa;R. Yokogawa;A. Ogura;Haidong Wang;Takanobu Watanabe
中科院分区：
文献类型：
--
作者：
S. Chung;M. Tomita;Junya Takizawa;R. Yokogawa;A. Ogura;Haidong Wang;Takanobu Watanabe
利用分子动力学方法，我们发现最近在非弹性x射线散射实验中发现的SiGe合金中的局域声子模谱会根据合金中成分团簇的尺寸分布而变化。通过改变Si和Ge的空间分布，可以得到不同Si和Ge团簇组成的合金模型。对于含有20%-80%锗的合金，小尺寸和中等尺寸的混合团簇将产生最高的局部模态强度。硅锗光模强度随局域模强度的增加而增加，但单靠硅锗键不足以产生局域模。具有小Ge团簇的富Si合金产生最高的局部模态强度，表明这种模态是由Si对包围的小Ge团簇引起的。
Using molecular dynamics, we found that the localized phonon-mode spectrum in SiGe alloys, which was recently discovered by an inelastic x-ray scattering experiment, changes according to the size distribution of compositional clusters in alloys. By varying the spatial distributions of Si and Ge, alloy models with differing compositions of Si and Ge clusters were able to be produced. For a range of alloys comprising 20%–80% Ge, a mixture of small and intermediate sized clusters will give the highest intensities of the local mode. The Si–Ge optical mode intensity increases with the local mode intensity, but the Si–Ge bond alone is not sufficient to produce the local mode. Si rich alloys with small Ge clusters produce the highest local mode intensities, suggesting that this mode is caused by small Ge clusters surrounded by Si pairs.