Zero-temperature Phase Diagram For Strongly-Correlated Nanochains

TL;DR

This paper investigates how the energy spacing in nanochains influences the competition between Kondo and RKKY interactions, revealing a phase diagram that could inform experimental control of magnetic states in nanoscale systems.

Contribution

It provides the first exact diagonalization study of the energy spacing's effect on the ground state of a dense Anderson nanochain, mapping out a zero-temperature phase diagram.

Findings

Energy spacing tunes Kondo-RKKY interplay

Identifies a free spins regime separating phases

Phase diagram relevant for quantum dot experiments

Abstract

Recently there has been a resurgence of intense experimental and theoretical interest on the Kondo physics of nanoscopic and mesoscopic systems due to the possibility of making experiments in extremely small samples. We have carried out exact diagonalization calculations to study the effect of the energy spacing $\Delta$ of the conduction band on the ground-state properties of a dense Anderson model nanochain. The calculations reveal for the first time that the energy spacing tunes the interplay between the Kondo and RKKY interactions, giving rise to a zero-temperature $\Delta$ versus hybridization phase diagram with regions of prevailing Kondo or RKKY correlations, separated by a {\it free spins} regime. This interplay may be relevant to experimental realizations of small rings or quantum dots with tunable magnetic properties.