反铁磁half-Heusler合金中反常霍尔和负磁阻效应及其物理机制研究

非共线反铁磁材料由于具有实空间非零的贝里曲率而表现出拓扑增强大的反常霍尔效应等新奇磁输运性质，是目前拓扑自旋电子学等领域研究的热点。本项目以我们前期工作中发现的具有大反常霍尔效应和负磁阻行为的反铁磁half-Heusler合金为研究研究对象，围绕磁场调控非平庸拓扑能带结构的物理机制这一关键科学问题，采用理论和实验相结合，重点研究其特殊的电子结构和独特的磁输运性质，阐明非平庸拓扑能带的形成及其与晶体结构和取向的关联。在此基础上，深入研究反铁磁half-Heusler合金中反常霍尔效应产生的物理机制和负磁阻效应的各向异性行为。项目将进一步尝试基于磁场调控能带结构的新材料探索研究，最终目标是建立设计half-Heusler合金拓扑材料的理论框架以及相关制备工艺。

Recently, the intrinsic anomalous hall effects (AHE) and its connection to the Berry curvature of the electronic bands have attracted significant attention in antiferromagnetic materials, and significant AHE in noncollinear antiferromagnets have been discovered. The project investigated the large AHE and negative magnetoresistance in noncollinear antiferromagnetic half-Heusler alloys, as well as their underlying physical mechanisms. On the one hand, we will investigate the large AHE and negative MR in a series of antiferromagnetic half-Heusler alloys, such as TbPtBi, HoPtBi, ErPtBi and TmPtBi. On the other hand, based on theoretical band calculations and the bulk quantum transport measurement in those half-Heusler alloys will be performed to offer an in-depth understanding the existence of a nontrivial berry phase. Understanding the effect of structure and orientation on AHE and negative MR, and the correlation between them in these topologically nontrivial half-Heusler alloys can exert great importance on exploration of new materials with better performance and new.applications.