Abstract
The magnon band topology due to the Dzyaloshinskii–Moriya interaction (DMI) and its relevant topological thermal Hall effect has been extensively studied in kagome lattice magnets. In this theoretical investigation, we report a new mechanism for phase transitions between topological phases of magnons in kagome ferromagnets by tuning the anisotropic nearest-neighbor ferromagnetic interaction and DMI. Using the linear spin-wave theory, we calculate the Chern number and thermal Hall conductivity of magnons in low temperature regime. We show the magnon band structures and magnonic edge states in each topological phase. From the topological phase diagram, we find a sign reversal of the thermal Hall conductivity upon tuning the modulation factors. We explicitly demonstrate the correspondence of thermal Hall conductivity with the propagation direction of the magnonic edge states. Finally, we discuss candidate materials as experimental realizations of our theoretical model.
Highlights
AcAUTHOR SUBMITTED MANUSCRIPT - NJP-114149.R1 ( ) SpinA, B, and C are placed at the corners of the a1 =(2stant,0 )a, aa.1, 3sublattices a. =triangles. η1, η2 and η3 are the modulation factors along A-B bondN earest-neighbour vectors:
The sign of κxy is governed by the sign of ν1 in low temperature regime as ν1 = C1
The propagation directions of edge states in the lower gap are opposite between the topological phases III and IV
Summary
(green line), B-C bond (blue line) and A-C bond (purple line) direc tions, respectively. - 3 2 avectors labeled by αi and βi. Hamiltonian our theoretical model results and method. Agram, topological magnon band structures, magnonic edge where modes, for(i,j)=(A,B), k=2 for(i,j)=(B,C), we end k=3 for (=A,C).
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
