Dielectric relaxation of the pinned spin-density wave in (TMTSF)2PF6

Abstract
The low-frequency dielectric response has been measured in the spin-density-wave state of (tetramethyltetraselenafulvalene)2 PF6. The dielectric constant is significantly larger than that expected for single-particle excitations and is dominated by the internal modes of the spin-density-wave condensate. We also established the relation between the frequency-dependent and nonlinear response.