Restricted path integral approach to the doped Hubbard model
Department of Theoretical Physics, Royal Institute of Technology, S-100 44 Stockholm, Sweden
Accepted: 5 December 1996
We present a restricted path integral approach to the 2D repulsive Hubbard model. It amounts to evaluating the partition function by restricting the summation over states to a small subclass and generalizes mean-field theory. Analyzing the simplest of these approximations, we find a mixed phase of fermions with local antiferromagnetic correlations coexisting with conventional metallic fermions. This mixed phase persists in a big parameter regime. We also discuss a refinement of our approximation which suggests simple explanations of several peculiar experimental features of HTSC.
PACS: 71.27.+a – Strongly correlated electron systems; heavy fermions / 21.60.Jz – Hartree-Fock and random-phase approximations / 74.72.-h – High-Tc compounds
© EDP Sciences, 1997