Imaging Pauli repulsion in scanning tunneling microscopy

TL;DR

This paper demonstrates a novel STM technique using a D2 molecule as a nanoscale force sensor to image Pauli repulsion, achieving ultra-high resolution of complex molecules on metal surfaces.

Contribution

It introduces a D2-based force sensor in STM that directly probes Pauli repulsion, providing new insights into molecular imaging at the nanoscale.

Findings

High-resolution images of organic molecules were obtained.

The sensor's mechanism was identified as detecting Pauli repulsion.

Conductance-distance spectroscopy correlated with density functional calculations.

Abstract

A scanning tunneling microscope (STM) has been equipped with a nanoscale force sensor and signal transducer composed of a single D2 molecule that is confined in the STM junction. The uncalibrated sensor is used to obtain ultra-high geometric image resolution of a complex organic molecule adsorbed on a noble metal surface. By means of conductance-distance spectroscopy and corresponding density functional calculations the mechanism of the sensor/transducer is identified. It probes the short-range Pauli repulsion and converts this signal into variations of the junction conductance.