title: Energy loss triggered by atomic-scale lateral force.
abstract: We perform bimodal atomic force microscopy measurements on a Br-doped NaCl (001) surface to investigate the mechanisms behind frequency shift and energy dissipation contrasts. The peculiar pattern of the dissipated energy in the torsional channel, related to frictional processes, is increased at the positions of Br impurities, otherwise indistinguishable from Cl ions in the other measured channels. Our simulations reveal how the energy dissipates by the rearrangement of the tip apex and how the process is ultimately governed by lateral forces. Even the slightest change in lateral forces, induced by the presence of a Br impurity, is enough to trigger the apex reconstruction more often, thus increasing the dissipation contrast; the predicted dissipation pattern and magnitude are in good quantitative agreement with the measurements.
authors.affiliation: Department of Physics, Tampere University of Technology, P.O. Box 692, FI-33010 Tampere, Finland and COMP, Department of Applied Physics, Aalto School of Science, P.O. Box 11100, FI-00076 Aalto, Finland.
authors.forename: Filippo
authors.initials: F
authors.lastname: Federici Canova
authors.affiliation: Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056 Basel, Switzerland.
authors.forename: Shigeki
authors.initials: S
authors.lastname: Kawai
authors.affiliation: Institute of Mineralogy and Petrography, University of Basel, Bernoullistrasse 30, CH-4056 Basel, Switzerland.
authors.forename: Christian
authors.initials: C
authors.lastname: de Capitani
authors.affiliation: Department of Material Science and Chemistry, Wakayama University, Wakayama 640-8510, Japan.
authors.forename: Ken-Ichi
authors.initials: K
authors.lastname: Kan'no
authors.affiliation: Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056 Basel, Switzerland.
authors.forename: Thilo
authors.initials: T
authors.lastname: Glatzel
authors.affiliation: Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056 Basel, Switzerland.
authors.forename: Bartosz
authors.initials: B
authors.lastname: Such
authors.affiliation: COMP, Department of Applied Physics, Aalto School of Science, P.O. Box 11100, FI-00076 Aalto, Finland.
authors.forename: Adam S
authors.initials: AS
authors.lastname: Foster
authors.affiliation: Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056 Basel, Switzerland.
authors.forename: Ernst
authors.initials: E
authors.lastname: Meyer