LOCALIZATION AND MAGNETIC-FIELD IN A QUASI-ONE-DIMENSIONAL CONDUCTOR

The semiclassical Boltzmann conductivity and the first quantum correction axe calculated for a strongly two-dimensional (2D) anisotropic conductor (weakly coupled chains system) in the presence of a magnetic field. From scaling arguments, the ground state of the system at zero temperature is determined. When the coupling t between chains is much smaller than the elastic scattering rate 1/tau, the system behaves as a set of uncoupled ID chains. In the other limit where 1/tau much less than t, the gas shows a 2D (anisotropic) behavior in zero field. A weak magnetic field leads to a negative magnetoresistance. As a consequence of the quasi-1D aspect of the Fermi surface, a strong magnetic field induces a transition from a 2D regime towards a 1D insulating state. The calculations are extended to the 3D case, where a magnetic field perpendicular to the chains can induce an Anderson localization.