Even-odd correlations in capacitance fluctuations of quantum dots

TL;DR

This paper studies how short-range interactions affect the addition spectra of quantum dots, revealing two regimes: one with even-odd fluctuations and another with structureless correlations at strong interactions.

Contribution

It introduces a correlation function (q) to analyze inverse compressibility data and identifies two distinct interaction regimes in quantum dots.

Findings

Two regimes of interaction strength identified: Fermi liquid-like and strongly correlated spins.

(q) shows structured fluctuations at weak interactions and becomes structureless at strong interactions.

Proposes magnetic correlations of localized spins as an explanation for the strong interaction regime.

Abstract

We investigate effects of short range interactions on the addition spectra of quantum dots using a disordered Hubbard model. A correlation function \cS(q) is defined on the inverse compressibility versus filling data, and computed numerically for small lattices. Two regimes of interaction strength are identified: the even/odd fluctuations regime typical of Fermi liquid ground states, and a regime of structureless $\cS(q)$ at strong interactions. We propose to understand the latter regime in terms of magnetically correlated localized spins.