Charge Sensing of an Artificial H2+ Molecule

TL;DR

This study demonstrates charge sensing of a controllable artificial H2+ molecule using a double quantum dot system, measuring charge states, tunnel coupling, and temperature with an integrated electrometer.

Contribution

It introduces a model accounting for electrostatic coupling and shows tunable tunnel coupling in a double quantum dot artificial molecule.

Findings

Tunable tunnel coupling between 0 and 60 μeV.

Accurate measurement of electron temperature and charge occupation.

Effective charge detection in a double quantum dot system.

Abstract

We report charge detection studies of a lateral double quantum dot with controllable charge states and tunable tunnel coupling. Using an integrated electrometer, we characterize the equilibrium state of a single electron trapped in the doubled-dot (artificial H2+ molecule) by measuring the average occupation of one dot. We present a model where the electrostatic coupling between the molecule and the sensor is taken into account explicitly. From the measurements, we extract the temperature of the isolated electron and the tunnel coupling energy. It is found that this coupling can be tuned between 0 and 60 micro electron-volt in our device.