Enhancement of long-range antiferromagnetic order by nonmagnetic impurities in the Hubbard model

• Published in: Europhysics letters Vol. 42; no. 6; pp. 655 - 660
• Main Authors: Ulmke, M, Denteneer, P. J. H, Scalettar, R. T, Zimanyi, G. T
• Format: Journal Article
• Language: English
• Published: IOP Publishing 15.06.1998; EDP Sciences
• Subjects: 71.27.+a; 71.30.+h
• ISSN: 0295-5075; 1286-4854
• DOI: 10.1209/epl/i1998-00301-2

The two-dimensional Hubbard model with a bimodal distribution of on-site interactions, $P(U_{\bf i})=(1-f)\delta(U_{\bf i}-U) +f\delta(U_{{\bf i}})$, is studied using finite-temperature Quantum Monte Carlo and dynamical mean-field theory. Long-range antiferromagnetic order off half-filling is stabilized by the disorder, due to localization of the dopants on the U=0 sites. Whereas in the clean model there is a single gap at n=1, for nonzero f we find the compressibility and density of states exhibit gaps at two separate fillings.