Scanning Quantum Dot Microscopy

TL;DR

This paper introduces a high-resolution scanning probe technique that images three-dimensional electrostatic potential fields at the nanoscale, enabling detailed analysis of molecular and atomic charge distributions.

Contribution

It presents a novel method combining atomic force microscopy with quantum dot charge detection to achieve sub-nanometer resolution in electrostatic potential imaging.

Findings

Successfully measured quadrupole field of a single molecule.

Quantified dipole field of a single metal adatom.

Achieved imaging of electrostatic potentials at large distances.

Abstract

Interactions between atomic and molecular objects are to a large extent defined by the nanoscale electrostatic potentials which these objects produce. We introduce a scanning probe technique that enables three-dimensional imaging of local electrostatic potential fields with sub-nanometer resolution. Registering single electron charging events of a molecular quantum dot attached to the tip of a (qPlus tuning fork) atomic force microscope operated at 5 K, we quantitatively measure the quadrupole field of a single molecule and the dipole field of a single metal adatom, both adsorbed on a clean metal surface. Because of its high sensitivity, the technique can record electrostatic potentials at large distances from their sources, which above all will help to image complex samples with increased surface roughness.