研究目的
Investigating the structural properties and intrinsic strain patterns of Si/Ge and Ge/Si core–shell nanowires using linear scaling density functional theory.
研究成果
The study demonstrates that linear scaling DFT is necessary for accurately determining the structural properties and intrinsic strain patterns of Si/Ge and Ge/Si core–shell nanowires. It highlights the limitations of Vegard’s law in predicting the axial lattice constant and reveals the complex, anisotropic strain patterns in the Ge component of the nanowires. The findings pave the way for future studies on the electronic properties of these nanowires and investigations into doping and structural defects.
研究不足
The study is limited to nanowires with diameters up to 10.2 nm and does not explore the electronic properties or the effects of doping and structural defects in detail. The computational demands of linear scaling DFT also limit the size of the systems that can be studied.
1：Experimental Design and Method Selection:
The study uses linear scaling density functional theory (DFT) to analyze the structural properties and intrinsic strain patterns of Si/Ge and Ge/Si core–shell nanowires. The methodology involves calculating the axial lattice parameters and analyzing the strain distribution within the nanowires.
2：Sample Selection and Data Sources:
The models examined include Si-core Ge-shell nanowires (SiGe-NWs) and Ge-core Si-shell nanowires (GeSi-NWs) with diameters ranging from 4.9 nm to 10.2 nm.
3：9 nm to 2 nm.
List of Experimental Equipment and Materials:
3. List of Experimental Equipment and Materials: The linear scaling DFT code Conquest was used for all calculations, employing the PBE GGA functional. The simulations were performed on systems containing up to 2404 atoms.
4：Experimental Procedures and Operational Workflow:
A two-stage relaxation process was used to find the optimal axial lattice parameter. The nanowire was structurally relaxed for a chosen lattice parameter, and this process was repeated for different values to find the lowest energy structure.
5：Data Analysis Methods:
The strain patterns were analyzed by projecting the average bond length onto a grid in a plane perpendicular to the nanowire axis, allowing for the visualization of strain variation with location and direction.
独家科研数据包，助您复现前沿成果，加速创新突破
获取完整内容
