Single molecule and single atom sensors for atomic resolution imaging of chemically complex surfaces

Area of Science:

• Atomic Force Microscopy
• Surface Science
• Nanotechnology

Background:

• Scanning tunneling microscopy (STM) is a powerful tool for atomic-scale imaging.
• Understanding short-range forces is crucial for characterizing molecular structures.
• Microscopic force sensing requires highly sensitive probes.

Purpose of the Study:

• To investigate the use of individual atoms and molecules as force sensors in STM.
• To demonstrate the ability of these sensors to image Pauli repulsion and molecular inner structures.
• To explore the tunability of sensor performance based on tip-adsorbate interactions.

Main Methods:

• Adsorbing individual Xenon (Xe) atoms, carbon monoxide (CO) molecules, and methane (CH4) molecules at the STM tip apex.
• Utilizing the STM tunneling current to detect forces exerted by the surface.
• Imaging large organic adsorbate molecules to resolve their inner structure.

Main Results:

• Xe atoms, CO, and CH4 molecules function effectively as microscopic force sensors.
• The STM sensors successfully imaged short-range Pauli repulsion forces.
• The inner structure of large organic adsorbate molecules was resolved.
• Sensor performance varied, indicating potential for tailored functionality.

Conclusions:

• Individual atoms and molecules can serve as versatile force sensors in STM.
• STM force sensing provides a method for resolving molecular details via Pauli repulsion imaging.
• Tailoring the sensor-tip interaction allows for optimization of force sensing capabilities.