Hybridization induced quantum phase transition in bilayer Hubbard model

TL;DR

This paper explores how strong interlayer hybridization in a bilayer Hubbard model induces a quantum phase transition, destroying superconductivity and leading to metallic and pseudogap phases, shedding light on pressure effects in layered materials.

Contribution

It provides a detailed phase diagram of the bilayer Hubbard model under hybridization, revealing the transition from superconducting to metallic phases due to hybridization effects.

Findings

Strong hybridization destroys $s^{}$-wave pairing.

Transition to correlated metallic, pseudogap, and Fermi liquid phases.

Phase diagram highlights pressure effects on layered Hubbard systems.

Abstract

Inspired by the recent experimental report on the pressure induced superconductor-insulator transition in cuprate superconductors as well as the superconductivity of the Ruddlesden-Popper-phase La$_3$Ni$_2$O$_7$ under high pressure, we systematically investigated the single-orbital bilayer Hubbard model in the regime of large interlayer hybridization to mimic the pressure effects. We map out the phase diagram of interlayer hybridization versus density in the regime of intermediate to strong hybridization. In particular, we found that the sufficiently strong hybridization can destroy the $s^{\pm}$-wave pairing and induces its transition to correlated metallic, pseudogap, and Fermi liquid phases depending on the doping regime. The phase diagram hosted by the bilayer model implies its role as the versatile platform to explore the pressure effects on the two-dimensional to three-dimensional crossover physics of Hubbard-type models.