Pairing correlations in the two-layer attractive Hubbard model
Scalettar, Richard T.
Batrouni, George G.
Date of Issue2014
School of Physical and Mathematical Sciences
Studies of systems with two fermionic bands (or equivalently, layers) with repulsive interaction strength U have a long history, with the periodic Anderson model (PAM) being one of the most frequently considered Hamiltonians. In this paper, we use quantum Monte Carlo to study analogous issues for attractive interactions. As in the PAM, we focus on a case where one band (layer) is uncorrelated (U = 0), and the effect of hybridization V between the bands (layers) on the pairing correlations. A key difference with the PAM is that there is no sign problem, so that we are better able to explore the physics of doped bilayer attractive systems at low temperatures (except in the case of exponentially small transition temperatures) whereas ground state properties of repulsive models can be determined only at half-filling. For small V , pairing in the U < 0 layer induces pairing in the U = 0 layer. At larger V superfluidity is suppressed at the low but finite T at which the quantum Monte Carlo was performed. The quantum Monte Carlo data are complemented by results obtained with the Bogoliubov–de Gennes approximation.
New journal of physics
© 2014 IOP Publishing Ltd and Deutsche Physikalische Gesellschaft. This paper was published in New Journal of Physics and is made available as an electronic reprint (preprint) with permission of IOP Publishing Ltd and Deutsche Physikalische Gesellschaft. The paper can be found at the following official DOI: [http://dx.doi.org/10.1088/1367-2630/16/1/013004]. One print or electronic copy may be made for personal use only. Systematic or multiple reproduction, distribution to multiple locations via electronic or other means, duplication of any material in this paper for a fee or for commercial purposes, or modification of the content of the paper is prohibited and is subject to penalties under law.