HALL-EFFECT IN THE MIXED-STATE OF MODERATELY CLEAN SUPERCONDUCTORS

The Hall conductivity in the mixed state of a clean (l much greater th an xi(0)) type-II s-wave superconductor is determined from a microscop ic calculation within a quasiclassical approximation. We find that bel ow the superconducting transition the contribution to the transverse c onductivity due to dynamical fluctuations of the order parameter is co mpensated by the modification of the quasiparticle contribution. In th is regime the nonlinear behaviour of the Hall angle is governed by the change in the effective quasiparticle scattering rate due to the redu ction in the density of states at the Fermi level. The connection with experimental results is discussed.