Title:Aspects of transport in magnets: hydrodynamics, topology, and noise
Speaker:Shu Zhang (Department of Physics, UCLA)
Time: 2021-08-27(周五) 10:00
Abstract:The exploration of transport phenomena of spin excitations, including magnons and topological spin textures, and pseudospin degrees of freedom is promising for the design of next-generation spintronic devices using magnetic insulators or semimetals. In this talk, I will give a brief overview of the hydrodynamic transport of topological spin textures based on topological conservation laws and their potential applications. Motivated from this perspective, we develop a thermodynamic view for the interplay between the real-space and momentum-space topologies, where the biased topological edge modes can be exploited to assist the injection of bulk topological charges, for example, skyrmions in the quantum Hall system and Majorana-carrying vortices in the p+ip topological superconductor. For the second part of my talk, I would like to introduce the idea of probing magnetic noise as a noninvasive approach for the study of spin and pseudospin transport, especially, since developments in nitrogen centers now enable high sensitivity and frequency resolution. Our most recent work proposes the detection of intrinsic valley transport in magnetic Weyl semimetals based on characteristics in their magnetic-noise spectra. If time permits, I will briefly talk about the topology in magnon-phonon hybridized excitations in antiferromagnets and the resulted thermal Hall effects.
 Y. Tserkovnyak, Journal of Applied Physics 124, 190901 (2018)
 M. T. Ahari*, S. Zhang*, J. Zou, and Y. Tserkovnyak, arXiv: 2104.01479
 S. Zhang and Y. Tserkovnyak, arXiv: 2108.07305
 S. Zhang, G. Go, K. J. Lee, and S. K. Kim, Physical Review Letters 124, 147204 (2020)