报告题目：Nonlinearity in an antiferromagnetic topological insulator
报告人：高安远 上海交通大学李政道研究所 anyuangao@sjtu.edu.cn
报告时间：2024年7月16日星期二，上午10-11点
报告地点：致远楼301
报告邀请人：陈垂针
报告摘要: Nonlinearities are crucial in many branches of physics, ranging from atomic physics to condensed matter and complex dynamical systems. Nonlinear electrical transport is the foundation of applications such as rectification and wave mixing. Classically, the most well-known nonlinear device is a PN diode. Noncentrosymmetric polar materials are similar to PN diodes as they both possess an electric dipole. They have recently been discovered to show intrinsic nonlinear electrical transport, which may not only lead to novel nonlinear applications but also provides a powerful probe of the quantum geometry of the conduction electrons. Broadly, the nonlinear transport in both diodes and noncentrosymmetric conductors arise from an inversion asymmetric charge distributions (e.g., an electric dipole). Because the electron has another fundamental degree of freedom, spin, an interesting question is whether spin can also lead to an electrical nonlinearity even in a centrosymmetric lattice. One ideal platform is the class of parity-inversion time-reversal (PT)-symmetric antiferromagnets (AFMs), where only the spins feature a noncentrosymmetric distribution. In this talk, I will introduce two interesting AFM spin induced nonlinear electrical transport in a PT-symmetric MnBi2Te4: 1.) AFM diode effect; 2.) quantum metric nonlinear Hall effect.
报告人简介：Anyuan Gao obtained his Ph.D. from the Department of Physics at Nanjing University in 2019. Following this, he conducted postdoctoral research at Harvard University from 2020 to 2024. In 2024, he joined the Tsung-Dao Lee Institute (TDLI) at Shanghai Jiao Tong University as an associate professor. In 2023, he received support from the National Talent Program, the Shanghai Overseas High-Level Talent Program, and the Shanghai Pujiang Talent Program. His research interests focus on understanding the electronic and optoelectronic properties of 2D quantum devices by optimizing device structure, electrical transport, and photocurrent measurements.
