LOCALIZATION IN HIGHLY ANISOTROPIC SYSTEMS AND ANOMALOUS RESISTIVITY IN CUPRATE-OXIDE SUPERCONDUCTORS

Anderson localization in highly anisotropic systems is briefly discuss ed, We point out that both the highly anisotropic band structure and t he anisotropic disordered potential may lead to metallic behaviors of the electric resistivity in one or two directions, and nonmetallic beh aviors of the electric resistivity in other directions, while the elec tron states on the Fermi surface are still extended in all directions. In particular, we found that when the disordered potential is anisotr opic, the electric resistivity in the nonmetallic direction approaches a saturated value as T --> 0, via a mechanism completely different fr om the mechanism proposed by Jonson and Girvin. These results are then used to qualitatively explain the anomalous behaviors of the electric resistivity in various cuprate-oxide superconducting samples.