Simple fit for magic-angle magnetoresistance in (TMTSF)₂PF₆

The angular-dependent magnetoresistance in the Bechgaard salts (TMTSF)₂X (X=PF₆, ClO₄, etc.) is characterized by sharp dips when the field is aligned along lattice vectors. Although magic-angle effects were originally predicted by Lebed, they remain largely unexplained. Here we present detailed interplane transport data and show that a simple model involving conductivity contributions from transfers between neighboring chains, which are individually destroyed by a perpendicular field, fits most c-axis data remarkably well. The fitting illustrates what can be explained by classical transport and what cannot - a dominant term from hopping perpendicular to the current direction. Combined with the observation that the fitting also "works" for a-axis data, this suggests a different interpretation: The quasi-one-dimensional system is insulating and any unnesting transfer makes it metallic.