Thermodynamics of the one-dimensional Hubbard model with next-nearest-neighbor hopping

摘要

For one-dimensional systems, Lieb and Mattis have proven that the ground state is unmagnetized, provided that the hopping is only between nearest neighbors. Recent studies suggest that the inclusion of next-nearest-neighbor hopping in the Hubbard model favors the long-range magnetic ordering. Contributing for a better understanding of the phenomenon, we have used the method of small-cluster exact diagonalization and the grand canonical quantum Monte Carlo method in order to study the temperature dependence of the specific heat, magnetic susceptibility and correlation functions. Our results show that the inclusion of the next-nearest-neighbor hopping (t(2)) causes the appearance of typical ferromagnetic properties which do not appear when t(2) = 0. (C) 2004 Elsevier B.V. All rights reserved.