Transport evidence for twin-boundary pinning of superconducting vortices in FeSe

We provide bulk transport evidence for twin-boundary pinning of vortices in FeSe. We measure interlayer resistance in FeSe in magnetic fields and find that, as the field is rotated in the $ab$ plane, the flux-flow resistivity is suppressed when the field direction is parallel to twinning planes. The width of the associated dip in the resistance vs in-plane field direction curve varies as ${T}^{1/2}{B}^{\ensuremath{-}3/4}$, consistent with the creation of kinked vortices near the parallel field geometry.