Delocalization due to correlations in two-dimensional disordered systems
Institut de Physique et Chimie des Matériaux de Strasbourg (UMR
7504 (CNRS-ULP)) , 23 rue du Loess, BP 43, 67034 Strasbourg Cedex 2, France
Corresponding author: a Dietmar.Weinmann@ipcms.u-strasbg.fr
Published online: 14 December 2004
We study the spectral statistics of interacting spin-less fermions in a two-dimensional disordered lattice. Within a full quantum treatment for small few-particle systems, we compute the low-energy many-body states numerically. While at weak disorder the interactions reduce spectral correlations and lead to localization, for the case of strong disorder we find that a moderate Coulomb interaction has a delocalizing effect. In addition, we observe a non-universal structure in the level-spacing distribution which we attribute to a mechanism reinforcing spectral correlations taking place in small systems at strong disorder.
PACS: 71.27.+a – Strongly correlated electron systems; heavy fermions / 73.20.Jc – Delocalization processes / 72.15.Rn – Localization effects (Anderson or weak localization)
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2004