Topological Hunds rules and the electronic properties of a triple lateral quantum dot molecule

TL;DR

This paper combines theoretical modeling and experimental measurements to understand the electronic structure of a triple quantum dot system, revealing topological Hund's rules that govern multi-electron energy levels and spin configurations.

Contribution

It introduces topological Hund's rules for triple quantum dots and validates them through combined theoretical analysis and experimental data.

Findings

Identification of topological Hund's rules governing energy levels.

Mapping of the charging diagram up to six electrons.

Prediction of a spin-polarized phase for two holes.

Abstract

We analyze theoretically and experimentally the electronic structure and charging diagram of three coupled lateral quantum dots filled with electrons. Using the Hubbard model and real-space exact diagonalization techniques we show that the electronic properties of this artificial molecule can be understood using a set of topological Hunds rules. These rules relate the multi-electron energy levels to spin and the inter-dot tunneling $t$, and control charging energies. We map out the charging diagram for up to N=6 electrons and predict a spin-polarized phase for two holes. The theoretical charging diagram is compared with the measured charging diagram of the gated triple-dot device.