Microwave Flux-flow Hall Effect in a Multi-band Superconductor FeSe

We have measured the flux-flow Hall effect in a multi-band superconductor FeSe pure single crystal to investigate the nature of the vortex core state by means of the cross-shaped bimodal cavity technique. We found that the flux-flow Hall angle of FeSe at low temperatures is about 0.5, which is equal to or smaller than that evaluated by the effective viscous drag coefficient measurements. This feature is in contrast to the cuprate superconductors. The conductivity tensor of multi-band superconductors that are contributed from holes and electrons shows partial cancellation of the flux-flow Hall voltage by the electrons and holes, which can explain the observed feature. Therefore, our study suggests the appearance of the multi-band nature in the vortex dynamics.