Hall constant of strongly correlated electrons on a ladder

The Hall constant R-H in a tight-binding model of correlated electrons on a ladder at T = 0 is expressed in terms of derivatives of the ground state e nergy with respect to external magnetic and electric fields. This novel met hod is used for the analysis of the t-J model on finite size ladders. It is found that for a single hole R-H is holelike and close to the semiclassica l value, while for two holes it can vary with ladder geometry. In odd-leg l adders, R-H behaves quite regularly changing sign as a function of doping, the variation being quantitatively close to experimental results in cuprate s.