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arXiv · 2012.12632

Topological spin-plasma waves

Dmitry K. Efimkin·Mehdi Kargarian
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Abstract

The surface of a topological insulator hosts Dirac electronic states with the spin-momentum locking, which constrains spin orientation perpendicular to electron momentum. As a result, collective plasma excitations in the interacting Dirac liquid manifest themselves as coupled charge- and spin-waves. Here we demonstrate that the presence of the spin component enables effective coupling between plasma waves and spin waves at interfaces between the surface of a topological insulator and insulating magnet. Moreover, the helical nature of spin-momentum locking textures provides the phase winding in the coupling between the spin and plasma waves that makes the spectrum of hybridized spin-plasma modes to be topologically nontrivial. We also show that such topological modes lead to a large thermal Hall response.

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Dmitry K. Efimkin, Mehdi Kargarian. 2020-12-23. Topological spin-plasma waves. https://doi.org/10.1103/physrevb.104.075413

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