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Novel Magnetoelectric Effect in Gyrotropic Crystals and the Current Induced Magnetization Switching

Date: 2023-06-01
Time: 14:00
Venue: MA428
Speaker: 贺文宇

上海科技大学   研究员

腾讯会议:453-872-071

会议密码:0601

会议链接:https://meeting.tencent.com/dm/Ab6Np9llo5qY

报告摘要

In noncentrosymmetric metals, current induced net magnetization is known as the magnetoelectric effect (or Edelstein effect). In past years, studies on the current driven magnetization mainly focused on polar crystals with Rashba spin-orbit coupling, where the magnetization is perpendicular to both the polar axis and current direction. Recently, many noncentrosymmetric materials emerge with various types of spin-orbit coupling and nonzero Berry curvature, but the magnetoelectric response there has not  been studied. In this talk, I will present the general theory for the current induced magnetization and show how the crystal symmetry determines the magnetoelectric response. In quasi-2D materials, we will show how the in-plane current can control out of plane magnetization and explain the recent observed DC current induced magnetization switching in twisted bilayer graphene. In crystals with chiral lattice symmetry, we will show that applying current can induce magnetization parallel to the current direction, which resembles the solenoid. We further extend our theory to the superconductivity region and show superconductors of gyrotropic point group symmetry can have novel magnetization driven by supercurrent, which does not have energy dissipation.

Reference:

1. Magnetoelectric effects in gyrotropic superconductors, W.-Y. He and K. T. Law, Phys. Rev. Research 2, 012073 (R) (2020).

2. Giant Orbital Magneto-electric effect and Current-driven Magnetization Switching in Twisted Bilayer Grpahene, W.-Y. He, David Goldhaber-Gordon, K. T. Law, Nat. Commun. 11, 1650 (2020).

3. Kramers Weyl Semimetals as Quantum Solenoids and Their Applications in Spin-Orbit Torque Devices, W.-Y. He, X. Y. Xu, and K. T. Law, Commun. Phys. 4, 66 (2021).

4. Superconducting Orbital Magnetoelectric Effect and its Evolution across the Superconductor-Normal Metal Phase Transition, W.-Y. He, and K. T. Law, Phys. Rev. Research 3, L032012 (2021).

报告人简介

贺文宇博士2013年本科毕业于北京师范大学物理学系,2018年博士毕业于香港科技大学物理学系,并在香港科技大学物理学系担任博士后研究员至2020年。随后,他赴麻省理工学院在Patrick A. Lee教授组担任博士研究员至2022年。在2022年四月,他加入上海科技大学物质科学与技术学院担任助理教授、研究员。贺文宇博士的研究领域集中在凝聚态物理,主要以二维过渡金属硫化物、双层有转角石墨烯和二维莫尔超晶格体系等二维量子材料为平台,研究其中出现的拓扑态、超导态和电子强关联效应。他的研究内容关注预言材料中的新物性和新物相,以及对实验中观测到的新现象提供物理解释。

邀 请 人:吴泉生 特聘研究员

联 系 人:王慧颖 why@iphy.ac.cn