Anisotropic electrodynamics of low dimensional metals: Optical studies of (TMTSF)2ClO4

Abstract. Optical experiments are reported for the metallic state of the linear chain compound (TMTSF)2ClO4. For the electric eld polarized both along the highly (a) and intermediately (b 0) conduct-ing directions, a zero energy (ZE) mode and a nite energy mode (FE) are observed. The large anisotropy in the spectral weight of the FE mode is consistent with the band structure, however the spectral weight of the ZE mode is surprisingly isotropic. In the least conducting (c) direction, the low frequency optical conductivity along with the dc conductivity indicate the presence of a (small) Drude component only at temperatures below 10 K. These observations provide evidence for a correlation induced semimetallic state, with a 3D to 2D crossover with increasing temperature. PACS. 78.20.-e Optical properties of bulk materials and thin lms { 71.10.Pm Fermions in reduced dimensions (anyons, composite fermions, Luttinger liquid, etc.) Fermi liquid (FL) theory has been the cornerstone of the theory of metals, and has been highly successful in ac-counting for the electronic properties of a wide range of materials. Recently, the breakdown of FL theory has bee