结构变化,表面状态和半导体Mg2Si和Ca2Si薄膜中的量子封闭效应之间的相互作用
A Yu Alekseev1, D B Migas1,2, A B Filonov1
1Belarusian State University of Informatics and Radioelectronics, P. Browki 6, 220013 Minsk, Belarus. migas@bsuir.by.
Physical chemistry chemical physics : PCCP
|July 17, 2023
概括
量子束显著改变了化 (Mg2Si) 和化 (Ca2Si) 薄膜的结构和带间隙. Mg2Si 薄膜显示间接带间隙,而 2D Mg2Si 显示直接带间隙.
科学领域:
- 计算材料科学科学 计算材料科学
- 固态物理 固态物理
- 薄膜物理学 薄膜物理学
背景情况:
- 像Mg2Si和Ca2Si这样的半导体化物对于热电应用至关重要.
- 了解薄膜中的量子束效应对于调整材料特性至关重要.
- 之前的研究已经探索了散装的特性,但薄膜的行为需要详细的调查.
研究的目的:
- 为了研究Mg2Si和Ca2Si薄膜中的结构转化.
- 为了分析这些电影中的带隙变化,由于量子束.
- 为了确定薄膜结构的稳定性和首选阶段.
主要方法:
- 首先利用计算技术来模拟薄膜的行为.
- 分析结构变化从散装到2D结构 (0.2纳米厚度).
- 计算带间隙和表面能量,以评估薄膜稳定性和电子性能.
主要成果:
- 立方Mg2Si111) 薄膜 (>0.3 nm) 显示动态稳定性和间接带间隙,可通过有效质量近似来减少.
- 2D Mg2Si 呈现出独特的 Orthorhombic 结构和直接带间隙.
- 由于表面能量较低,在厚度<3 nm的情况下,超稳定立方Ca2Si(111) 薄膜在能量上比奥托罗姆比相更受青.
- Ca2Si薄膜 (<3 nm) 显示结构扭曲和表面状态,导致带隙异常依赖厚度.
结论:
- 量子封闭显著影响Mg2Si和Ca2Si薄膜的结构和电子特性.
- 这些材料可以实现厚度依赖的相位稳定性和带隙工程.
- 这些发现为设计基于化物的新型电子和热电器件提供了洞察力.
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