Quantum Effect Between Object and Probe Could Enable Higher Resolution AFM

A novel technique, dubbed quantum atomic force microscopy, has the potential to significantly enhance the spatial, spectral and temporal resolution of AFM for nanometrology of materials.

Researchers at Oak Ridge National Laboratory (ORNL) have introduced the concept of a quantum-mechanical modality that capitalizes on squeezed states of probe displacement. The technique tracks the minute interactions between the probe of the microscope and the surface of the sample to locate the precise point where quantum effects stabilize the probe, resulting in more sensitive measurements.

When two objects approach each other, an interfacial interaction force becomes significant. By using this force, one may utilize quantum effects to advantageously control the motion of the probe. Courtesy of ORNL.

“That’s the theoretical prediction of this effect,” said researcher Ali Passian. “Of course, the experiments will have the final say on how much better we can do, but the basic concept and theory are viable.”

Researchers showed that squeezing was enabled nanomechanically when the probe entered the van der Waals regime of interaction with a sample. They studied the effect in noncontact mode, where the parameter domains characterizing the attractive regime of the probe-sample interaction force could be evaluated.

The research was published in Physical Review A (doi: 10.1103/PhysRevA.95.043812).