CAREER: Role of Symmetry in the Properties of Nanostructures: A First Principles Approach

这一学院早期职业发展(CALEAR)计划将开发一种廉价的高保真计算框架，用于加速发现具有前所未有的性能的纳米结构，这些结构可以根据技术应用而定制。纳米结构可以被定义为在纳米范围内至少具有一维的结构。这些系统所显示的显著特性导致了纳米技术的革命性领域，其潜在应用包括有效地生产和储存可再生能源；诊断和治愈绝症；有效的净化工艺；以及合成高强度/重量比的新材料。设计具有增强性能的纳米结构的能力尤其重要，这些纳米结构非常适合于这种应用。然而，天文数字的大量纳米结构配置和组成使系统的搜索变得不切实际。因此，目前的实验和计算技术通常依赖于经验洞察力，这使得这个过程漫长、昂贵并且容易失败。综合教育目标是将多学科纳米科学/纳米技术相关课程纳入K-12、本科生和研究生教育。纳米结构的对称性，无论是完整的还是破碎的，在决定其非凡性能方面发挥着关键作用。为了理解和利用这种依赖关系，将发展一种新的实空间、对称性适应的公式和从头算密度泛函理论的大规模并行实现。该公式与所有对称基团的兼容性将导致计算成本的极大降低，从而能够准确地表征尺寸比目前可行的纳米结构大三个数量级的纳米结构。此外，所开发的配方将允许使用对称性对纳米结构的构型空间进行有效的参数化，从而系统地发现具有深奥性质的新的纳米结构。将要研究的应用包括纳米级的挠曲电性，它将提供对极化和应变梯度之间耦合的性质和强度的新的理解；T4噬菌体病毒尾鞘的相变，这将为病毒的结构和创造提供重要的见解；以及通过线性弥散关系寻找显示独特现象的新的纳米结构。总体而言，这项研究代表着一种范式的转变，不同于传统的观点，即具有平移对称的晶体单胞是基本的构建块。

This Faculty Early Career Development (CAREER) program will develop an inexpensive high-fidelity computational framework for the accelerated discovery of nanostructures with unprecedented properties that can be tailored to technological applications. Nanostructures can be defined as structures which possess at least one dimension in the nanometer range. The remarkable properties displayed by such systems have resulted in the revolutionary field of nanotechnology, whose potential applications include the efficient production and storage of renewable energy; diagnosis and cure of terminal illnesses; effective purification processes; and synthesis of new materials with high strength to weight ratio. The capability to design nanostructures with enhanced properties that are well suited to such applications is of particular importance. However, the astronomically large number of nanostructure configurations and compositions makes a systematic search impractical. Therefore, current experimental and computational techniques typically rely on empirical insight, which makes the process lengthy, expensive and susceptible to failure. The integrated educational objective is to incorporate multi-disciplinary nanoscience/nanotechnology related curriculum into the K-12, undergraduate and graduate education. The symmetry of nanostructures, either intact or broken, plays a key role in determining their extraordinary properties. Towards the goal of understanding and utilizing this dependence, a novel real-space, symmetry-adapted formulation and massively parallel implementation of ab-initio Density Functional Theory will be developed. The compatibility of this formulation with all the symmetry groups will result in a tremendous reduction in the computational cost, thereby enabling the accurate characterization of nanostructures that are three orders of magnitude larger in size than those currently feasible. Additionally, the developed formulation will enable the systematic discovery of new nanostructures with esoteric properties by allowing for an efficient parametrization of the configurational space of nanostructures using symmetry. The applications to be studied include nanoscale flexoelectricity, which will provide new understanding into the nature and strength of the coupling between polarization and strain gradients; phase transformation of the tail sheath in the bacteriophage T4 virus, which will provide significant insights into the structure and creation of viruses; and search for new nanostructures that display unique phenomena by virtue of a linear dispersion relation. Overall, the proposed research represents a paradigm shift from the conventional view that crystal unit cells with translational symmetry are the fundamental building blocks.