Magnetism in one-dimensional quantum dot arrays

TL;DR

This study uses density functional theory to explore how quantum dot arrays in one dimension develop magnetic properties, revealing transitions from non-magnetic to magnetic states influenced by dot spacing and electron filling.

Contribution

It demonstrates the emergence of magnetism and spin-polarized transport in quantum dot arrays based on their geometric and electronic configurations.

Findings

Quantum wires become magnetic as dots are spaced further apart.

Spin-Peierls transition occurs with increased confinement perpendicular to the wire.

Arrays can support spin-polarized transport at larger lattice constants.

Abstract

We employ the density functional Kohn-Sham method in the local spin-density approximation to study the electronic structure and magnetism of quasi one-dimensional periodic arrays of few-electron quantum dots. At small values of the lattice constant, the single dots overlap, forming a non-magnetic quantum wire with nearly homogenous density. As the confinement perpendicular to the wire is increased, i.e. as the wire is squeezed to become more one-dimensional, it undergoes a spin-Peierls transition. Magnetism sets in as the quantum dots are placed further apart. It is determined by the electronic shell filling of the individual quantum dots. At larger values of the lattice constant, the band structure for odd numbers of electrons per dot indicates that the array could support spin-polarized transport and therefore act as a spin filter.