The (111) surface of CaF$_2$ has been intensively studied with
large-amplitude frequency-modulation atomic force microscopy and atomic
contrast formation is now well understood. It has been shown that the apparent
contrast patterns obtained with a polar tip strongly depend on the tip
terminating ion and three sub-lattices of anions and cations can be imaged.
Here, we study the details of atomic contrast formation on CaF$_2$(111) with
small-amplitude force microscopy utilizing the qPlus sensor that has been shown
to provide utmost resolution at high scanning stability. Step edges resulting
from cleaving crystals in-situ in the ultra-high vacuum appear as very sharp
structures and on flat terraces, the atomic corrugation is seen in high clarity
even for large area scans. The atomic structure is also not lost when scanning
across triple layer step edges. High resolution scans of small surface areas
yield contrast features of anion- and cation sub-lattices with unprecedented
resolution. These contrast patterns are related to previously reported
theoretical results.Comment: 18 pages, 9 Figures, presented at 7th Int Conf Noncontact AFM
  Seattle, USA Sep 12-15 2004, accepted for publication in Nanotechnology,
  http://www.iop.or

Allers W

Barth C

Foster A

Franz J Giessibl

Giessibl F J

Israelachvili J

Letz M

Michael Reichling

Reichling M

Schick M

Tasker P W

English

arXiv

The (111) surface of CaF₂ has been intensively studied with large-amplitude frequency-modulation atomic force microscopy, and the atomic contrast formation is now well understood. It has been shown that the apparent contrast patterns obtained with a polar tip strongly depend on the tip terminating ion, and three sub-lattices of anions and cations can be imaged. Here, we study the details of atomic contrast formation on CaF₂(111) with small-amplitude force microscopy utilizing the qPlus sensor that has been shown to provide the utmost resolution at high scanning stability. Step edges resulting from cleaving crystals in situ in the ultra-high vacuum appear as very sharp structures, and on flat terraces the atomic corrugation is seen in high clarity even for large area scans. The atomic structure is also not lost when scanning across triple layer step edges. High-resolution scans of small surface areas yield contrast features of anion- and cation sub-lattices with unprecedented resolution. These contrast patterns are related to previously reported theoretical results

Giessibl, Franz J.

Reichling, Michael

University of Regensburg Publication Server

Investigating atomic details of the CaF₂(111) surface with a qPlus sensor

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