Dr Dmitry Efimkin
The surface of a topological insulator hosts Dirac electronic states with the peculiar spin-momentum locking. It implies that the direction of electron’s spin is strictly determined by its momentum. As a result, collective excitations of interacting Dirac liquid at the surface manifest themselves as coupled charge- and spin-waves, and have been referred as spin-plasmons [1,2].
In my talk, I will consider the coupling between magnons and spin-plasmons at the interface between a topological insulator and an insulating magnet. I will argue, that the spin-momentum locking of Dirac electrons introduces the phase winding factors to the coupling between spin-plasmons and magnons and dispersions of the hybrid modes formed by them becomes topologically nontrivial.
[2] S Raghu, S B Chung, X L Qi, and S C Zhang – Phys. Rev. Lett. 104, 116401– 116405 (2010).
About the presenter
Dr Dmitry Efimkin is a Scientific Associate Investigator at Monash University specialising in novel materials such as Dirac materials, graphene and topological insulators, and optical phenomena in solids. Within FLEET, Dmitry works with Michael Fuhrer, Meera Parish, and Nkhil Medhekar in Research theme 2: exciton superfluids and Enabling technology A: atomically-thin materials, studying optical and collective phenomena in novel 2D materials, and correlations and transport in bi-layer systems, including electron-hole condensation and the Coulomb drag effect. He is also interested in condensation of spatially separated electrons and holes and manifestations including dipolar superfluidity.