Singlet-triplet transitions in highly correlated nanowire quantum dots

TL;DR

This study models two-electron quantum dots in nanowires, revealing tunable singlet-triplet transitions influenced by aspect ratio, magnetic field, and electron correlations, highlighting the system's highly correlated nature.

Contribution

Develops a configuration interaction theory to analyze singlet-triplet transitions in nanowire quantum dots with tunable aspect ratios.

Findings

Singlet-triplet transitions depend on aspect ratio and magnetic field.

Transitions are driven by exchange, correlation, and Zeeman energies.

High aspect ratio dots show highly correlated electron behavior.

Abstract

We consider a quantum dot embedded in a three-dimensional nanowire with tunable aspect ratio a. A configuration interaction theory is developed to calculate the energy spectra of the finite 1D quantum dot systems charged with two electrons in the presence of magnetic fields B along the wire axis. Fruitful singlet-triplet transition behaviors are revealed and explained in terms of the competing exchange interaction, correlation interaction, and spin Zeeman energy. In the high aspect ratio regime, the singlet-triplet transitions are shown designable by tuning the parameters a and B. The transitions also manifest the highly correlated nature of long nanowire quantum dots.