SINGULARITY OF THE DENSITY-OF-STATES IN THE 2-DIMENSIONAL HUBBARD-MODEL FROM FINITE-SIZE-SCALING OF YANG-LEE ZEROS

A finite-size scaling is applied to the Yang-Lee zeros of the grand ca nonical partition function for the two-dimensional Hubbard model in th e complex chemical potential plane. The logarithmic scaling of the ima ginary part of the zeros with the system size indicates a singular dep endence of the carrier density on the chemical potential. Our analysis points to a second-order phase transition with critical exponent 1/de lta(=)1/2+/-1/3 which leads to a divergence of the electronic suscepti bility. We interpret these results as reflecting the singular behavior of the density of states in the quasiparticle spectrum.