ANDERSON LOCALIZATION IN ANISOTROPIC ELECTRONIC SYSTEMS UNDER THE INFLUENCE OF WEAK EXTERNAL ELECTRIC AND MAGNETIC-FIELDS

The self-consistent diagrammatic theory derived by Vollhardt and Wolfe has been phenomenologically extended to treat the influence of small electric and magnetic fields on the Anderson localization in disordere d anisotropic systems. The approach describes the combined effect of c onstant electric and magnetic fields as well as the anisotropy of the material on the metal-insulator phase boundary. Known limiting cases a re reproduced. The theory is expected to give a consistent picture of field-dependent transport measurements even in such cases where the di sorder is comparatively large (k(F) lambda(0) greater than or similar to 1) and the perturbation theory is inapplicable.