Charge density wave dynamics on ring

We have studied a topological effect of a charge density wave (CDW) in niobium triselenide ring crystals. We measured the frequency dependence of AC conductivity in the range from 300 kHz to 1.3 GHz to investigate the dynamics of the CDW ring. We compared the dynamical properties of the CDW in the ring and in the cut-ring geometries. The experimental data shows that the pinning frequency of the cut-ring is larger than that of the ring. This result suggests that the dynamics of the CDW depend on the edges, i.e., the topological structure of the sample.