The topological magnon bands in the Flux state in Sashtry-Sutherland lattice

Abstract

We investigate low energy magnon excitations above the non-collinear flux state and non-coplanar canted flux state in a Heisenberg anti-ferromagnet with Dzyaloshinskii-Moriya interaction~(DMI) on a Sashtry-Sutherland lattice.While previous studies have shown the presence of topological magnetic excitation in the dimer and ferromagnetic phases on the Shastry-Sutherland lattice, our results establish the non-trivial topology of magnons in the anti-ferromagnetic flux and canted flux states. Our results uncover the existence of a multitude of topological phase transitions in the magnon sector -- evidenced by the changing Chern numbers of the single magnon bands -- as the Hamiltonian parameters are varied, even when the ground state remains unchanged. The thermal Hall conductivity is calculated and its derivative is shown to exhibit a logarithmic divergence at the phase transitions, independent of the type of band touching involved. This may provide a useful means to identify the energy at which the transition occurs. Finally, we propose the way to realize the studied model in a practical material.

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• Magnon Hall effect in antiferromagnetic lattices
• Quantum phases of spin-1/2 extended XY model in transverse magnetic field
• Tuning bulk topological magnon properties with light-induced magnons
• Topological characterization of magnon-polaron bands and thermal Hall conductivity in a frustrated kagome antiferromagnet
• Magnon topology driven by altermagnetism
• U(1)-Symmetry protected Dirac nodal loops of triplons in SrCu2(BO3)2