School of Physics, Quantum Matter Seminar|Dr. Shu Zhangi | Max Planck Institute 

Spin caloritronics explores the interplay between spin and heat transport for the development of future spintronic thermal devices[1]. 

In magnetic insulators, magnons play the major role in transporting spin degree of freedom, while both magnons and phonons contribute to heat transport. The coupled transport of thermally excited magnons and phonons can be further enriched by the topology of their band structure. In this talk, I will show that hybridized magnon-phonon excitations with nontrivial topology can arise from magnetoelastic coupling, which generally exist in magnetic materials with crystalline anisotropy[2]. Such a scheme can be quite generic since it does not rely on inversion-breaking spin interactions, chiral magnetic ground states, nor long-range dipolar interactions, as we demonstrate in a collinear antiferromagnet[3]. The thermal Hall transport as a result of the magnon-phonon topology can exhibit switching effects across topological phase transitions in an applied magnetic field, which may be of practical interest in spincaloritronic applications. I will discuss our predictions in the context of van der Waals magnetic materials.

[1]. G. Bauer, E. Saitoh, and B. van Wees, Nat. Mater. 11, 391 (2012)

[2]. C. Kittel, Rev. Mod. Phys. 21, 541 (1949)

[3]. S Zhang, G Go, K. J. Lee, and S. K. Kim, Phys. Rev. Lett. 124, 147204 (2020