Eur. Phys. J. B 19, 25-36 (2001)
https://doi.org/10.1007/s100510170347

Integrable correlated electron model with next-nearest-neighbour interactions

¹ Max Planck Institut für Physik Komplexer Systeme, Nöthnitzer Str. 38, 01187 Dresden, Germany
² B.I. Verkin Institute for Low Temperature Physics and Engineering of the Ukrainian National Academy of Sciences, 47, Lenin Avenue, Kharkov 61164, Ukraine
³ Universität Dortmund, Fachbereich Physik, Otto-Hahn-Str. 4, 44221 Dortmund, Germany
⁴ Institut für Theoretische Physik, Universität zu Köln, Zülpicher Str. 77, 50937 Köln, Germany

Corresponding author: ^a zvyagin@mpipks-dresden.mpg.de

Received: 13 September 2000
Published online: 15 January 2001

Abstract

The exactly solvable model of supersymmetric chains (STJC) of correlated electrons with next-nearest-neighbour (NNN) interactions is proposed and studied. The model with interactions between nearest neighbours and NNN interactions in one chain can also be considered as a two-chain model with zigzag-like coupling between the chains. The NNN interaction (coupling between chains) causes the onset of additional Dirac seas for low-lying charge and/or spin excitations. These Dirac seas change the low-energy (conformal) behavior of the model. The filling of those seas depends on the values of the NNN coupling (interactions between chains), external magnetic field and applied voltage. We identify the new ground state phases which appear due to the NNN as incommensurate ones. The NNN coupling in the incommensurate phases induces spontaneous magnetization and/or spontaneous filling of the Dirac sea for charge excitations ("spontaneous charge ordering"). The onset of this order implies a first order quantum phase transition driven by the field with hysteresis phenomena.