Hall effect in high- Tc superconductors

Abstract

The Hall coefficient ( R H) in high- T c cuprates behaves as R H∝ T −1 below a characteristic temperature T 0 (≲1000 K), and R H≫1/ ne at low temperatures in under-doped compounds. Concerning the resistivity ( ρ), d ρ/d T increases below T 0 in LSCO experimentally. In the present paper, we give a theoretical explanation of these long-standing problems from the standpoint of the nearly antiferromagnetic Fermi liquids. We study the vertex corrections for the current using a conserving approximation, and find out that they give anomalous behaviors for both R H and ρ. The numerical results for R H and ρ obtained by the fluctuation-exchange (FLEX) approximation are consistent with the experiments.