Signatures of Wigner Localization in Epitaxially Grown Nanowires

TL;DR

This paper demonstrates the detection of Wigner molecule formation in InSb nanowire quantum dots through transport measurements, providing experimental and theoretical evidence of electron localization at low densities.

Contribution

It introduces a combined theoretical and experimental approach to identify Wigner localization signatures in nanowire quantum dots, advancing the understanding of electron crystallization.

Findings

Identification of Wigner state signatures in transport data

Suppression of antiferromagnetic coupling as a Wigner indicator

Detection of Wigner localization onset by varying dot size

Abstract

It was predicted by Wigner in 1934 that the electron gas will undergo a transition to a crystallized state when its density is very low. Whereas significant progress has been made towards the detection of electronic Wigner states, their clear and direct experimental verification still remains a challenge. Here we address signatures of Wigner molecule formation in the transport properties of InSb nanowire quantum dot systems, where a few electrons may form localized states depending on the size of the dot (i.e. the electron density). By a configuration interaction approach combined with an appropriate transport formalism, we are able to predict the transport properties of these systems, in excellent agreement with experimental data. We identify specific signatures of Wigner state formation, such as the strong suppression of the antiferromagnetic coupling, and are able to detect the onset of Wigner localization, both experimentally and theoretically, by studying different dot sizes.