Hall-sign dependent on dimensionality of vortex-pinning disorder

The vortex-glass (VG) fluctuation contribution sigma(xy)(vg) to the Hall conductivity in the vortex liquid regime of layered superconductors under a field perpendicular to the layers is perturbatively studied by taking account both of point-like and line-like pinning disorders. A calculation of a few low order terms of sigma(xy)(vg) with respect to the pinning strengths suggests that, in the case including only line disorders, the ratio r(gf) equivalent to sigma(xy)(vg)/sigma(xy)(vf) < 0, while r(gf) > 0 in sufficiently 3D-like systems including only point disorders, where sigma(xy)(vf) is the vortex flow contribution to the Hall conductivity. In the general case with both line-like and point-like disorders, the sign of r(gf) is not determined merely by the nature of the VG transition but seems to depend on the relative amount of point-like and line-like disorders and on the dimensionality of thermal fluctuation. Recent data relevant to this issue are discussed based on the present result. (C) 1999 Elsevier Science B.V. All rights reserved.