ITMO University , Saint Petersburg 197101, Russia.
Department of Electronic Engineering, Shanghai Jiao Tong University , Shanghai 200240, China.
Nano Lett. 2017 Sep 13;17(9):5514-5520. doi: 10.1021/acs.nanolett.7b02203. Epub 2017 Aug 4.
Engineering nanostructured optical materials via the purposeful distortion of their constituent nanocrystals requires the knowledge of how various distortions affect the nanocrystals' electronic subsystem and its interaction with light. We use the geometric theory of defects in solids to calculate the linear permittivity tensor of semiconductor nanocrystals whose crystal lattice is arbitrarily distorted by imperfections or strains. The result is then employed to systematically analyze the optical properties of nanocrystals with spatial dispersion caused by screw dislocations and Eshelby twists. We demonstrate that Eshelby twists create gyrotropy in nanocrystals made of isotropic semiconductors whereas screw dislocations can produce it only if the nanocrystal material itself is inherently anisotropic. We also show that the dependence of circular dichroism spectrum on the aspect ratio of dislocation-distorted semiconductor nanorods allows resonant enhancing their optical activity (at least by a factor of 2) and creating highly optically active nanomaterials.
通过有目的地扭曲组成纳米晶体的方法来设计纳米结构光学材料，需要了解各种扭曲如何影响纳米晶体的电子子系统及其与光的相互作用。我们使用固体位错理论来计算由晶体缺陷或应变任意扭曲的半导体纳米晶体的线性介电张量。然后，利用该结果系统地分析由螺旋位错和埃舍尔扭曲引起的空间分散的纳米晶体的光学性质。我们证明，埃舍尔扭曲在各向同性半导体纳米晶体中产生旋光性，而只有当纳米晶体材料本身固有各向异性时，螺旋位错才能产生旋光性。我们还表明，对于由位错扭曲的半导体纳米棒的纵横比的依赖关系允许共振增强其圆二色性（至少提高 2 倍）并创建高光学活性的纳米材料。
