Flexible drift-compensation system for precise 3D force mapping in severe drift environments

Abstract

The acquisition of dense 3D data sets is of great importance, but also a challenge for scanning probe microscopy (SPM). Thermal drift often induces severe distortions in the data, which usually constrains the acquisition of dense data sets to experiments under ultra-high vacuum and low-temperature conditions. Atom tracking is an elegant approach to compensate for thermal drift and to position the microscope tip with highest precision. Here, we present a flexible drift compensation system which can easily be connected to existing SPM hardware. Furthermore, we describe a 3D data acquisition and position correction protocol, which is capable of handling large and non-linear drift as typically present in room temperature measurements. This protocol is based on atom-tracking for precise positioning of the tip and we are able to acquire dense 3D data sets over several hours at room temperature. The performance of the protocol is demonstrated by presenting 3D data taken on a CaCO(3)(10 ̅14) surface with the data density being as large as 85×85×500 pixel.

Unique Determination of “Subatomic” Contrast by Imaging Covalent Backbonding

“…During constant height imaging, a custom-built atom tracking unit 27 was used in order to both measure, and then correct thermal drift by applying feedforward correction in between each scan.…”

Identifying the absolute orientation of a low-symmetry surface in real space

“…Utmost measurement stability is required and established at room temperature using a home-built atom-tracking system [21] for drift measurement and compensation [22]. A complex scan protocol of alternating steps of drift compensation and data acquisition is implemented [21] and described in Sec.…”

Mechanochemistry at the Single Bond Limit: Towards `Deterministic Epitaxy'

“…All experimental work will involve III-V(110) substrates due to both their ease of preparation via cleavage and lack of mid-gap surface states (at least for well-cleaved samples), and will be carried out under ultrahigh vacuum conditions and at a temperature of either 77 K or 5K. In line with our recent work [5,7], to eliminate thermal drift we will use an atom-tracking facility developed by Philipp Rahe [8] and co-workers [32]. As discussed below, the atom-tracking capability is essential in order to accurately measure force-distance curves for their subsequent comparison to those generated by DFT calculations.…”