EAGER: Universal transport and diamagnetic signatures in non-magnetic topological semimetals with linear magnetoresistance

非技术摘要：材料的电学性质是由材料中电子的量子力学运动决定的。材料可以是导电性很低的绝缘体，也可以是导电性很高的金属，这取决于带负电荷的电子在静止和带正电的原子核之间的运动方式。有些材料是半金属的，其性质介于金属和绝缘体之间。最近，拓扑半集引起了人们的极大兴趣，拓扑学在决定拓扑半集的性质中起着重要作用。本项目将研究拓扑半金属在强磁场下的导电性，以确定其独特的特性。这些结果将使实验室测试能够将拓扑半金属与更传统的拓扑半金属区分开来，并确定在技术应用中将遇到的条件下拓扑特征的稳健性。这些结果可直接用于开发制造技术和器件设计策略，以将拓扑半金属的新特性和功能融入创新技术中。技术摘要：本项目旨在识别将拓扑半金属与具有大的非饱和磁阻(MR)的传统半金属区分开来的磁输运和抗磁特征。这些结果将阐明拓扑半金属的普遍特征，即拓扑电子结构和相关的Berry相的独特特征。将建立一个框架来描述在高场极限下导致线性MR出现的无序的特征，这有望使人们更好地理解无序在一般的线性MR现象中的作用。由于拓扑节点和频带结构中线性色散的结果而出现线性MR的预测将在更广泛的半金属系统中进行测试，并将揭示线性非饱和MR现象的共同元素。该奖项反映了NSF的法定使命，并已通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Non-technical Absttract:The electrical properties of materials are governed by the quantum mechanical motion of electrons in the material. Materials can be insulators, with very low electrical conductivity, or metals, with high electrical conductivity, depending on how the negatively charged electrons move amongst the stationary and positively charged atomic nuclei. Some materials are semimetals where the properties lie between those of metals and insulators. Recently there has been a great deal of interest in topological semimetals where topology plays a major role in determining their properties. This project will investigate the electrical conduction of topological semimetals under high magnetic field to pinpoint their unique characteristics. The results will enable laboratory tests to separate topological semimetals from more conventional counterparts, and to determine the robustness of topological characteristics under conditions that would be encountered in technological applications. These outcomes can be directly employed in developing fabrication techniques and device design strategies to incorporate the novel properties and functionality of topological semimetals in innovative technologies.Technical Abstract:This project aims to identify the magnetotransport and diamagnetic signatures that distinguish topological semimetals from conventional semimetals with large non-saturating magnetoresistance (MR). The outcomes will clarify the universal features of topological semimetal that are unique characteristics of topological electronic structures and the associated Berry phase. A framework will be developed to characterize the disorder leading to the emergence of linear MR in the high field limit, which is expected to render a better understanding of the roles of disorder in linear MR phenomena in general. The prediction for the emergence of linear MR as a consequence of topological nodes and linear dispersion in band structure will be tested for a broader range of semimetal systems and will uncover the common elements of the linear non-saturating MR phenomena.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.