Universal Perpendicular Conductivity of a Layered Conductor in a Parallel Magnetic Field

We suggested an original method to investigate Fermi surfaces (FS’s) in quasi-two-dimensional (Q2D) conductors 25 years ago [A.G. Lebed and N.N. Bagmet, Phys. Rev. B 55, R8654 (1997)]. It was based on a consideration of a perpendicular conductivity in Q2D metals in the framework of Boltzmann kinetic equation, where it was shown that the conductivity is independent on impurities in a high parallel magnetic fields. In this paper, we demonstrate that this result is more general than the kinetic equation and can be obtained even in a fully quantum mechanical case. The above mentioned statement is shown to be valid even in the case, where the typical "sizes" of the quasi-classical electron orbits are less or of the order of the inter-plane distances in Q2D conductors. We suggest to investigate this possible universal conductivity in Q2D organic and high-T_c superconductors in a metallic phase to judge if the Fermi liquid (FL) picture is valid or not. If the FL picture is valid, then study of the perpendicular conductivity allows to extract important information about the Q2D FS's.