@Article{CiCP-25-651,
author = {Yueguang Shi and Warren E. Pickett},
title = {Study of Simulation Cell Size in Mean-Field Studies of Interacting Lattice Models},
journal = {Communications in Computational Physics},
year = {2018},
volume = {25},
number = {3},
pages = {651--668},
abstract = {<p style="text-align: justify;">A lattice model of interacting fermions is studied with the principal aim
of assessing the dependence of calculated mean-field ground states versus the N×N lattice size, with N=16, 32, and 48. A two band model on the two-dimensional
square lattice is simulated, with on-site energies and interaction parameters chosen
to represent crystal field split orbitals in the moderately correlated regime. Nearest
neighbor hopping leads to the well known van Hove singularities (vHs) of the square
lattice. Anomalies in the inverse participation ratio of the eigenstates are found to be
associated with the vHs, with their prevalence decreasing inversely with N. For the
chosen model, inhomogeneous spin densities are always obtained for the small lattice
size N=16, with the degree of variation decreasing rapidly for most polarizations as N
is increased. Various spin polarizations are treated, and one case in which spin density
inhomogeneity persists for the largest lattice size is discussed and analyzed. Coupling
of spin density inhomogeneities to charge density variation is minor but evident, and
is primarily of intra-orbital origin.</p>},
issn = {1991-7120},
doi = {https://doi.org/10.4208/cicp.OA-2018-0089},
url = {http://global-sci.org/intro/article_detail/cicp/12824.html}
}