THE HALL CONSTANT OF CORRELATED ELECTRONS - CLUSTER CALCULATION FOR HUBBARD-MODEL

We calculate the Hall constant R(H)(omega, T) for the high T-c materia ls La2-xSrxCuO4 and YBa2Cu3O7-x using the 2D Hubbard model, on a clust er of dimension (2 x 3). Close to half filling, at low temperatures an d high frequency, we find that R(H)(omega) is electronlike in the weak correlation regime and in the strong correlation regime it is holelik e with roughly 1/T + const form. At high frequencies, for La2-xSrxCuO4 we obtain a change in the sign of R(H)(omega) at x similar to 0.3, wh ich is in good agreement with the experimental data.