周惠久论坛——Manipulation of the quantum-metric structure in a topological chiral antiferromagnet

时间：2024年12月27日  上午11：00

地点：兴庆校区 仲英楼 材料学院 第一会议室（A245）

讲座人：憨家豪  副教授

讲座人介绍：憨家豪，2016年于清华大学材料学院获学士学位，2022年于美国麻省理工学院电气工程与计算机科学系获博士学位。2022年起在日本东北大学任博士后研究员、助理教授、副教授。主要研究方向为自旋电子学及拓扑材料，以第一或通讯作者在Science、Nature Materials、Nature Nanotechnology、Nature Physics等期刊发表论文，在APS March Meeting、MMM、Intermag等国际学术会议做邀请报告。主持日本学术振兴会青年项目和外国人特别研究员项目。获得2022年美国物理学会磁学优秀毕业论文奖（distinguished dissertation award）。

讲座摘要：The quantum metric and Berry curvature are two fundamental and distinct factors that describe the geometry of quantum eigenstates. While the role of the Berry curvature in governing various condensed-matter states has been investigated extensively, the quantum metric, which was also predicted to induce topological phenomena of equal importance, has rarely been studied. Recently, a breakthrough has been made in observing the quantum-metric nonlinear transport in a van der Waals magnet, but the effect was limited at cryogenic temperature and was tuned by strong magnetic fields of several teslas. In our study, we demonstrated room-temperature manipulation of the quantum-metric structure of electronic states through its interplay with the interfacial spin texture in a topological chiral antiferromagnet/heavy metal Mn3Sn/Pt heterostructure, which was manifested in a time-reversal-odd second-order Hall effect. We showed the flexibility of controlling the quantum-metric structure with moderate magnetic fields and verified the quantum-metric origin of the observed second-order Hall effect by theoretical modeling. Our results opened the possibility of building applicable nonlinear devices by harnessing the quantum-metric structure of electronic states.

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主办单位：

材料学院

金属材料强度国家重点实验室