Non-analytical magnetoresistance and a new method of investigation of Fermi surfaces in Q2D and Q1D conductors

We demonstrate that transverse magnetoresistance is a non-analytical function of a magnetic field, ρ⊥ ∼ |H|^1/2, if a magnetic field is normal to quasi-two-dimensional (Q2D) Fermi surface (FS) at an inflexion point. Recently discovered Osada-Kagoshima angular resonance is described in terms of the existence of an inflexion point on the FS of (TMTSF)₂ClO₄-conductor. It is shown that at arbitrary direction of a magnetic field in a 2D plane transverse magnetoresistance does not depend on electron relaxation time and obeys a linear law, ρ⊥ ∼ A|H|, where A depends on some local characteristics of a Q2D FS. The above mentioned effects provide us with a new method of investigation of FS's in strongly anisotropic Q2D (Q1D) conductors.