Field-induced confinement in quasi-one-dimensional organic conductors

We show within a quantum -mechanical calculation that in Bechgaard salts the electron transport along the least conducting c axis is dramatically affected by a magnetic field applied parallel to the intermediate conducting b axis. Above a threshold field, the system undergoes a field-induced dimensional crossover from a three-dimensional (3D) phase to a two-dimensional phase where the electrons are confined in the most conducting (ab) plane. This leads to a significant change in the temperature dependence of the electron scattering rate. The latter exhibits strong deviations from the T(2) Fermi-liquid (FL) rule, which is only obeyed in the low-temperature 3D phase where the interplane hopping is coherent. Despite the departure of the scattering rate from the FL behavior, the transport properties at high temperature are found to be in accordance with FL predictions. Our results, which correctly account for the c-axis transport measurements in Bechgaard salts, provide a possible understanding of the striking behavior of the interlayer conductivity in cuprate based compounds in a parallel magnetic field.