Irradiation Effects and the Role of Disorder in Low Dimensional Conductors

Abstract

Abstract The concentration of defects produced by irradiation can be measured by several independent methods such as longitudinal and transverse conductivity measurements at room temperature, spin susceptibility at low temperature, volume or lattice parameters change. The physical consequences of this kind of disorder are as follows. The superconductivity in (TMTSF)2PF6 is destroyed by a molecular concentration of 10−4. The concentration of 2.10−3 corresponds to the full pinning of charge density waves in monoclinic TaS3, 1T-TaS2, TTF-TCNQ, TMTSF-DMFCNQ… Microdiffraction experiments demonstrate some structural aspects of this pinning and conductivity, Hall effect and thermoelectric power measurements demonstrate the consequences of the pinning on the electronic properties of several low temperature charge density wave insulators. In most of the cases the metallic state is stabilized by a weak disorder. The problem of the charge density wave motion in presence of defects is discussed in connection with the...