Speaker: Prof. Yue Zhang, Huazhong University of Science and Technology
Time: 14:30-15:30 , Oct.29
Location: SIST 1C 101
Host: Prof. Zhifeng Zhu
Abstract:
Emission of terahertz (THz) wave has potential application in information technology (like 6G communication) and biological medicine. An antiferromagnetic (AFM) medium is a potential candidate for exciting THz magnetization dynamics owing to its strong exchange coupling. However, the central frequency for the AFM dynamics is generally above 1 THz, which limits its wide application in different fields. This talk presents our recent calculation about the AFM dynamics of various frequency bands based on different physical principles. The talk covers the following contents: (1) We show that the DW emits a pulsed sub-THz spin-wave package during the inertia-induced acceleration/deceleration process. This is analogous to the bremsstrahlung of a charged particle. (2) Also by exploiting the inertial motion of AFM DW at a low velocity, we propose the excitation of a low-frequency (MHz) DW oscillation driven by spatially inhomogeneous strain, which is analogous to a classical pendulum. (3) Based on the massive relativistic-like property of an AFM DW, we predict the excitation of THz magnon with discrete spectrum, which satisfies Einstein’s mass-energy transition. (4) We also propose optical-acoustic excitation of AFM THz spin wave with a wide frequency band by manipulating the Dzyaloshinskii-Moriya interaction.
Bio:
Yue Zhang is an associate professor working in School of Optical and Electronic Information in Huazhong University of Science and Technology. He graduated from Wuhan University in 2011 as a PHD majored in the condensed-matter physics. He visited Prof. Chialing Chien’s lab in the Department of Physics and Astronomy in Johns Hopkins University between 2016 and 2018. Currently, he is interested in the calculation of magnetization dynamics of novel magnetic textures and its application in artificial intelligence. Also, he is experimentally studying the physical mechanism for the magnetoresistance and anomalous Hall effect of nonmagnetic/magnetic multilayers. He has published more than 60 papers with about 1200 citations.