Partially Gapped Fermions in 2D
2010 (English)In: Journal of statistical physics, ISSN 0022-4715, E-ISSN 1572-9613, Vol. 139, no 6, 1033-1065 p.Article in journal (Refereed) Published
We compute mean field phase diagrams of two closely related interacting fermion models in two spatial dimensions (2D). The first is the so-called 2D t-t'-V model describing spinless fermions on a square lattice with local hopping and density-density interactions. The second is the so-called 2D Luttinger model that provides an effective description of the 2D t-t'-V model and in which parts of the fermion degrees of freedom are treated exactly by bosonization. In mean field theory, both models have a charge-density-wave (CDW) instability making them gapped at half-filling. The 2D t-t'-V model has a significant parameter regime away from half-filling where neither the CDW nor the normal state are thermodynamically stable. We show that the 2D Luttinger model allows to obtain more detailed information about this mixed region. In particular, we find in the 2D Luttinger model a partially gapped phase that, as we argue, can be described by an exactly solvable model.
Place, publisher, year, edition, pages
2010. Vol. 139, no 6, 1033-1065 p.
2D lattice fermion systems, Phase diagrams, Mean field theory
Other Physics Topics
IdentifiersURN: urn:nbn:se:kth:diva-27875DOI: 10.1007/s10955-010-9971-2ISI: 000277715600007ScopusID: 2-s2.0-77952412411OAI: oai:DiVA.org:kth-27875DiVA: diva2:385420
QC 201101112011-01-112011-01-032011-12-07Bibliographically approved