Anomalous temperature dependence of resistivity in quasi-one-dimensional conductors in a strong magnetic field

We present a heuristic, semiphenomenological model of the anomalous temperature (T) dependence of resistivity ρ <Subscript> xx </Subscript> recently observed experimentally in the quasi-one-dimensional (Q1D) organic conductors of the (TMTSF)<Subscript>2</Subscript>X family in moderately strong magnetic fields. We suggest that a Q1D conductor behaves like an insulator (dρ <Subscript> xx </Subscript>/dT > 0), when its effective dimensionality is one, and like a metal (dρ <Subscript> xx </Subscript>/dT > 0), when its effective dimensionality is greater than one. Applying a magnetic field reduces the effective dimensionality of the system and switches the temperature dependence of resistivity between the insulating and metallic laws depending on the magnitude and orientation of the magnetic field. We critically analyze whether various microscopic models suggested in literature can produce such a behavior and find that none of the models is fully satisfactory. In particular, we perform detailed analytical and numerical calculations within the scenario of magnetic-field-induced spin-density-wave precursor effect suggested by Gor’kov and find that the theoretical results do not agree with the experimental observations. Copyright Società Italiana di Fisica, Springer-Verlag 1999