Connecting single-layer $t$-$J$ to Kondo lattice models: Exploration with cold atoms

TL;DR

This paper proposes using ultracold atom experiments in a bilayer Hubbard setup to simulate Kondo lattice physics, revealing insights into the connection between high-temperature superconductivity and heavy-fermion behavior.

Contribution

It introduces a mixed-dimensional bilayer Hubbard platform to study Kondo physics and links the phase diagrams of cuprates and heavy-fermion materials through tunable parameters.

Findings

Kondo cloud formation observed at feasible temperatures

Competition between singlet formation and RKKY interactions demonstrated

Continuous tuning between $t$-$J$ and Kondo lattice regimes shown

Abstract

The Kondo effect, a hallmark of many-body physics, emerges from the antiferromagnetic coupling between localized spins and conduction fermions, leading to a correlated many-body singlet state. Here we propose to use the mixed-dimensional (mixD) bilayer Hubbard geometry as a platform to study Kondo lattice physics with current ultracold atom experiments. At experimentally feasible temperatures, we predict that key features of the Kondo effect can be observed, including formation of the Kondo cloud around a single impurity and the competition of singlet formation with Ruderman-Kittel-Kasuya-Yosida (RKKY) interactions for multiple impurities, summarized in the Doniach phase diagram. Moreover, we show that the mixD platform provides a natural bridge between the Doniach phase diagram of the Kondo lattice model, relevant to heavy-fermion materials, and the phase diagram of cuprate superconductors as described by a single-layer Zhang-Rice type $t$-$J$ model: It is possible to continuously tune between the two regimes by changing the interlayer Kondo coupling. Our findings demonstrate that the direct connection between high-temperature superconductivity and heavy-fermion physics can be experimentally studied using currently available quantum simulation platforms.