Layered superconductor in a magnetic field: breakdown of the effective masses model
A. G. Lebed
Department of Physics, University of Arizona, 1118 E. 4-th Street, AZ 85721 Tucson, USA
L. D. Landau Institute for Theoretical Physics, Russian Academy of Sciences, 117334 Moscow, Russia
Abstract
We theoretically study the upper critical magnetic fields at zero
temperature in a quasi-two-dimensional (Q2D) superconductor in the
parallel and perpendicular fields, and
(0), respectively. We find that
and that , where and are the
corresponding Ginzburg-Landau slopes of the upper critical
magnetic fields. Our results demonstrate the breakdown of the
so-called effective mass model in Q2D case and may be partially
responsible for the experimentally observed deviations from the
effective mass model in a number of layered superconductors,
including MgB2.