Pairing correlations in the two-layer attractive Hubbard model

Abstract

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 6

Topological transitions in a model for proximity-induced superconductivity

“…1 (a)-(d)). Eventually, beyond a critical value of the interlayer hopping superconductivity ceases to exist in both the layers in agreement with the previous report on proximity effect [32].…”

Superconducting Kondo phase in an orbitally separated bilayer

“…Indeed, such strategy has proved fruitful, for instance, in the case of Ce-based superlattices [26], and more recently in the twisted bilayer graphene [27,28], which revealed a wealth of interesting magnetic and superconducting phenomena. We should mention that proximity effects have been studied in the context of the Hubbard model in a layered geometry [29,30], resulting in an induced pairing in the adjacent layers; electron-phonon coupling could also provide the appearance of superconductivity in Kondo insulators, by combining the Holstein model with the PAM [31][32][33].…”

Superfluidity and density order in a bilayer extended Hubbard model

“…Superfluidity and possible modes of pairing were investigated using the dynamical cluster approximation with repulsive intralayer interactions [11] and by Monte Carlo simulations with attractive ones [12]. The magnetic properties of the repulsive model were explored in Ref.…”

“…Motivated by the variety of experimental systems, several theoretical and computational studies have explored the physics of bilayer or other two-band Hubbard models. Superfluidity and possible modes of pairing were investigated using the dynamical cluster approximation with repulsive intralayer interactions 11 and by Monte Carlo simulations with attractive ones 12 . The magnetic properties of the repulsive model were explored in 13 .…”