Hall Responses in Larger Spin Quantum Magnets*

Phenomena related to nontrivial band topology and transverse transports have recently gained enormous interest. Including spin degrees of freedom, a new branch of Hall responses has been proposed and observed. The concept of (anomalous/spin) Hall and (anomalous/spin) Nernst effects spread quickly from the electronic systems to magnetic excitations, leading to magnon-mediated Hall responses [1-7].

We consider magnetic insulators characterized by a larger spin and therefore by spin-multipolar degrees of freedom. We investigate the topology of the multipolar excitations and discuss the spin Nernst and thermal Hall effects arising for the nontrivial magnon modes.

Furthermore, we address the multipole character of the nontrivial bands with focus on possible new experimental detection of nontrivial magnon-band topology due to these additional degrees of freedom.

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