Seminar "Topological magnons in Kitaev magnets at high fields" by Prof. Karlo Penc

Speaker

Prof. Karlo Penc / Wigner Research Centre for Physics, Budapest, Hungary

Abstract

We study the Kitaev-Heisenberg model that describes the magnetism in spin-orbit coupled honeycomb lattice Mott insulators. In strong magnetic fields  that bring the system into the fully polarized paramagnetic phase, we find that the spin-wave bands carry nontrivial Chern numbers over large regions of the phase diagram, implying the presence of chiral magnon edge states. In contrast to other topological magnon systems, the topological nontriviality of these systems results from the presence of anisotropic terms in the Hamiltonian that do not conserve the number of magnons. Using time-dependent density matrix renormalization group methods and interacting spin-wave theory, we demonstrate the presence of the chiral edge mode and its evolution with field.