Magnon spin-orbit coupling effects in magnetic insulators
By Prof. Ka Shen, Department of Physics, Beijing Normal University, Beijing, China
Tuesday, May 30
3:30 – 4:30 p.m.
Building 9, Level 3, Room 3220
Abstract
Different from the situation in ferromagnets, antiferromagnets and ferrimagnets can host both left- and right-handed circularly polarized magnon modes, which, very similar to the spin states of electrons, carry opposite angular momenta. In this talk, we will discuss the possibility of realizing the spin-orbit coupling effects of these magnon states in insulators, as analogues of the spin-orbit coupling effects of itinerant electrons in metals. Specifically, we will show that the dipole-dipole interaction, naturally existing in magnetic materials, can introduce an effective magnon spin-orbit coupling and give rise to electron-like spin-orbit phenomena, such as an intrinsic magnon spin Hall effect and D’yakonov-Perel’-type magnon spin relaxation [1,2]. In addition, the dipolar-induced magnon spin-orbit coupling can also lead to various topological magnon phases [3-5], including nodal-line semimetal and Weyl semimetal phases, which present surface magnon states with spin-momentum locking. Our work suggests that the antiferromagnetic and ferrimagnetic insulators could be suitable platforms for exploring electron-like spin dynamics in insulators and designing novel magnonic devices.
About the speaker
Ka Shen is a professor at the Department of Physics, Beijing Normal University, China. He is a researcher in theoretical condensed matter physics, particularly interested in spintronics, magnonics, spin caloritronics, and spin dynamics. Prof. Ka Shen received his B.S. and Ph.D. from the University of Science and Technology of China, China. He worked as a postdoctoral scholar with Prof. G. Vignale at the University of Missouri, and Prof. Gerrit E. W. Bauer at the Delft University of Technology, respectively. He has published numerous papers as the first author or corresponding author in prestigious journals, such as Physical Review Letters, Physical Review B, and Advanced Materials. He has received many awards, including 1000 talent program of China and Distinguished Youth scholar of NSF.
