Mapping reservoir-enhanced superconductivity to near-long-range magnetic order in the undoped one-dimensional Anderson and Kondo lattices

Abstract

The undoped Kondo necklace in 1D is a paradigmatic and well understood model of a Kondo insulator. This work performs the first large-scale study of the 1D Anderson lattice underlying the Kondo necklace with quasiexact numerical methods, comparing this with the perturbative effective 1D Kondo necklace model derived from the former. This study is based on an exact mapping of the Anderson model to one of a superconducting pairing layer connected to a metallic reservoir, which is valid in arbitrary spatial dimensions, thereby linking the previously disparate areas of reservoir-enhanced superconductivity, following Kivelson's pioneering proposals, and that of periodic Kondo systems. Our work reveals that below the lengthscales on which the insulating state sets in, which can be very large, superconducting and density-density correlations are degenerate and may both appear to approach an almost ordered state, to a degree that far exceeds that of any isolated 1D pairing layer with short-range interactions. We trace these effects to the effective extended-range coupling that the metallic layer mediates within the pairing layer. These results translate directly to the appearance of near-long-range magnetic order at intermediate scales in the Kondo systems, and explain the strong renormalization of the RKKYcoupling that we effectively observe, in terms of the back-action of the pairing layer onto the metallic layer. The effects we predict could be tested either by local probes of quasi1D heavy fermion compounds such as CeCo2Ga8, in engineered chains of adatoms or in ultracold atomic gases.

Source-reported materials — not catalogue approval

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