Some results on the phase diagram of the 2D Hubbard model using an analytic Lanczos method

• Published in: Physica. B, Condensed matter Vol. 259; pp. 766 - 768
• Main Authors: Wellard, C.J., Witte, N.S., Hollenberg, L.C.L.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 1999
• Subjects: Hubbard Model; Lanczos method; Linked cluster expansion method; Magnetic phase diagram; 05.30.−d; 75.10.Jm; 71.10.Pm; 11.15.Tk; Magnetic phase diagram; Linked cluster expansion method; Hubbard Model; Lanczos method
• ISSN: 0921-4526; 1873-2135
• DOI: 10.1016/S0921-4526(98)00722-4

Aspects of the ground state phase diagram of the two-dimensional Hubbard model have been determined using a new non-perturbative method based on an analytic formulation of the Lanczos algorithm. The ground state energy for arbitrary repulsion
U/
t and density
n has been calculated using a number of trial states which are expected to be qualitatively correct in certain regimes of this model – the paramagnetic Fermi sea and the Hartree–Fock spin density wave state. We find large corrections to the mean-field result that shift the paramagnetic–ferromagnetic transition to higher values of
U/
t and closer to half-filling.