https://doi.org/10.1140/epjb/e2009-00389-6
Deconfinement phase transition in a two-dimensional model of interacting 2 × 2 plaquettes
Physics Department, University of Wuppertal, 42097 Wuppertal, Germany
Corresponding author: a fledderj@physik.uni-wuppertal.de
Received:
5
November
2008
Revised:
21
September
2009
Published online:
20
November
2009
A two-dimensional model of interacting plaquettes is studied by means of the real space renormalization group approach. Interactions between the plaquettes are mediated solely by spin excitations on the plaquettes. Depending on the plaquette-plaquette coupling J, we find two regimes: “confinement” Jc < J ≤ 1, where the singlet ground state forms an infinite (“confined”) cluster in the thermodynamical limit. Here the singlet-triplet gap vanishes, which is the signature for long range spin-spin correlators. “deconfinement” 0 ≤ J < Jc, where the singlet ground state “deconfines” – i.e. factorizes – into finite n-clusters of size 2n × 2n, with n ≤ nc(J). Here the singlet-triplet gap is finite. The critical value turns out to be Jc = 0.4822...
PACS: 71.10.Fd – Lattice fermion models / 71.27.+a – Strongly correlated electron systems; heavy fermions / 75.10.-b – General theory and models of magnetic ordering / 75.10.Jm – Quantized spin models
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2009
