Eur. Phys. J. B 23, 57-67 (2001)
https://doi.org/10.1007/s100510170082

Competition of disorder and interchain hopping in a two-chain Hubbard model

¹ LPTENS (CNRS-UMR 8549) 24, rue Lhomond 75231 Paris Cedex 05, France
² Department of Physics, Nagoya University, Nagoya 464-8602, Japan and CREST, Japan Science and Technology Corporation (JST), Japan

Corresponding author: ^a orignac@lpt.ens.fr

Received: 6 April 2001
Published online: 15 September 2001

Abstract

We study the interplay of Anderson localization and interaction in a two chain Hubbard ladder allowing for arbitrary ratio of disorder strength to interchain coupling. We obtain three different types of spin gapped localized phases depending on the strength of disorder: a pinned 4k_F Charge Density Wave (CDW) for weak disorder, a pinned 2k_F CDW_π for intermediate disorder and two independently pinned single chain 2k_F CDW for strong disorder. Confinement of electrons can be obtained as a result of strong disorder or strong attraction. We give the full phase diagram as a function of disorder, interaction strength and interchain hopping. We also study the influence of interchain hopping on localization length and show that localization is enhanced by a small interchain hopping but suppressed by a large interchain hopping.