The Influence of Long-Range Hopping on Ferromagnetism in the Hubbard Model on the Generalized Shastry-Sutherland Lattice

摘要

The projector quantum Monte-Carlo method is used to examine effects of long-range electron hopping on ferromagnetism in the Hubbard model on the generalized Shastry-Sutherland lattice. It is shown that the long-range electron hopping with the exponentially decaying hopping amplitudes tij()approximate to e-|tabilizes the ferromagnetic state for a wide range of electron hopping , electron interactions U, and electron concentrations n above the half-filled band case n =1. The critical value of the hopping parameter (c), below which the ferromagnetic state becomes stable, is calculated numerically and the ground-state phase diagram of the model in the n - plane is presented for physically the most interesting case of the intermediate Coulomb interactions.