Theory of single atom manipulation with a scanning probe tip: Force signatures, constant-height, and constant-force scans

TL;DR

This paper presents a theoretical study on manipulating a silver atom on a silicon surface using a scanning probe tip, analyzing force signatures and different manipulation modes to inform experimental techniques.

Contribution

It introduces a combined quantum chemistry and analytical model to predict atom manipulation methods and force signatures in scanning probe microscopy.

Findings

Four manipulation modes identified in constant-height mode

Force signatures correlate with manipulation processes

Manipulation feasible with Si(111) tips across various conditions

Abstract

We report theoretical results predicting the atomic manipulation of a silver atom on a Si(001) surface by a scanning probe tip, and providing insight into the manipulation phenomena. A molecular mechanics technique has been used, the system being described by a quantum chemistry method for the short-range interactions and an analytical model for the long-range ones. Taking into account several shapes, orientations, and chemical natures of the scanning tip, we observed four different ways to manipulate the deposited atom in a constant-height mode. In particular, the manipulation is predicted to be possible with a Si(111) tip for different tip shapes and adatom locations on the silicon surface. The calculation of the forces during the manipulation revealed that specific variations can be associated with each kind of process. These force signatures, such as the tip height signatures observed in scanning tunneling microscope experiments, could be used to deduce the process involved in an experiment. Finally, we present preliminary results about the manipulation in constant-force mode.