Field-Dependent Dielectric Response of the Three-Dimensional Charge-Density Wave in K0.3MoO3

The dielectric response of K0.3MoO3 was investigated both in the charge-density-wave (CDW) chain axis and in the inter-chain direction. At sufficiently low frequencies, the anomalous rise in the dielectric constant e(T) was observed isotropically, indicating three-dimensionality of the CDW condensate. On the other hand, e(T) curves are highly sensitive to ac field in the chain direction. The anomaly was inferred to be caused by hopping of the charged phase defects, which is apparently inconsistent with the glassy CDW picture.