Theory of unusual anisotropy of magnetoresistance in organic superconductors

We suggest that weak electron tunneling between layers is responsible for the experimentally observed dramatic deviations from two-dimensional behavior in the magnetoresistance in the metallic phase of the quasi-two-dimensional conductors (TMTSF${)}_2$ ${\mathrm{ClO}}_4$ and (TMTSF${)}_2$ ${\mathrm{PF}}_6$. We predict a fine structure due to resonances in open orbits between motion parallel and perpendicular to the planes.