Molecular phases in coupled quantum dots

TL;DR

This paper investigates the excitation spectra of few-electron coupled quantum dots under magnetic fields, revealing atomic-like and novel molecular-like phases, and demonstrating control over the isospin index which characterizes the artificial molecule's bonding.

Contribution

It introduces the identification of molecular-like phases in coupled quantum dots and demonstrates control over the isospin index related to the bonding nature.

Findings

Observation of ground state transitions induced by magnetic fields.

Identification of molecular-like phases in coupled quantum dots.

Control over the isospin index to manipulate the bond character.

Abstract

We present excitation energy spectra of few-electron vertically coupled quantum dots for strong and intermediate inter-dot coupling. By applying a magnetic field, we induce ground state transitions and identify the corresponding quantum numbers by comparison with few-body calculations. In addition to atomic-like states, we find novel "molecular-like" phases. The isospin index characterizes the nature of the bond of the artificial molecule and this we control. Like spin in a single quantum dot, transitions in isospin leading to full polarization are observed with increasing magnetic field.