Title:Aspects of transport in magnets: hydrodynamics, topology, and noise

Speaker:Shu Zhang (Department of Physics, UCLA)

Location:理科楼C109

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[1] 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[2], 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[3] 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[4].

[1] Y. Tserkovnyak, Journal of Applied Physics 124, 190901 (2018)

[2] M. T. Ahari*, S. Zhang*, J. Zou, and Y. Tserkovnyak, arXiv: 2104.01479

[3] S. Zhang and Y. Tserkovnyak, arXiv: 2108.07305

[4] S. Zhang, G. Go, K. J. Lee, and S. K. Kim, Physical Review Letters 124, 147204 (2020)