title: Giant frictional dissipation peaks and charge-density-wave slips at the NbSe2 surface.
abstract: Understanding nanoscale friction and dissipation is central to nanotechnology. The recent detection of the electronic-friction drop caused by the onset of superconductivity in Nb by means of an ultrasensitive non-contact pendulum atomic force microscope (AFM) raised hopes that a wider variety of mechanical-dissipation mechanisms become accessible. Here, we report a multiplet of AFM dissipation peaks arising a few nanometres above the surface of NbSe2--a layered compound exhibiting an incommensurate charge-density wave (CDW). Each peak appears at a well-defined tip-surface interaction force of the order of a nanonewton, and persists up to 70 K, where the short-range order of CDWs is known to disappear. Comparison of the measurements with a theoretical model suggests that the peaks are associated with local, tip-induced 2π phase slips of the CDW, and that dissipation maxima arise from hysteretic behaviour of the CDW phase as the tip oscillates at specific distances where sharp local slips occur.
authors: Department of Physics, University of Basel, Klingelbergstraße 82, Basel 4056, Switzerland.
authors: Markus
authors: M
authors: Langer
authors: Department of Physics, University of Basel, Klingelbergstraße 82, Basel 4056, Switzerland.
authors: Marcin
authors: M
authors: Kisiel
authors: Department of Physics, University of Basel, Klingelbergstraße 82, Basel 4056, Switzerland.
authors: Rémy
authors: R
authors: Pawlak
authors: 1] SISSA, Via Bonomea 265, Trieste 34136, Italy [2] CNR-IOM Democritos National Simulation Center, Via Bonomea 265, Trieste I-34136, Italy.
authors: Franco
authors: F
authors: Pellegrini
authors: 1] SISSA, Via Bonomea 265, Trieste 34136, Italy [2] CNR-IOM Democritos National Simulation Center, Via Bonomea 265, Trieste I-34136, Italy [3] International Centre for Theoretical Physics (ICTP), PO Box 586, Trieste I-34014, Italy.
authors: Giuseppe E
authors: GE
authors: Santoro
authors: CNR-SPIN Institute for Superconductivity, Innovative Materials and Devices, C.so Perrone 24, Genova 16152, Italy.
authors: Renato
authors: R
authors: Buzio
authors: CNR-SPIN Institute for Superconductivity, Innovative Materials and Devices, C.so Perrone 24, Genova 16152, Italy.
authors: Andrea
authors: A
authors: Gerbi
authors: Department of Physics, University of Warwick, Coventry CV4 7AL, UK.
authors: Geetha
authors: G
authors: Balakrishnan
authors: Department of Physics, University of Basel, Klingelbergstraße 82, Basel 4056, Switzerland.
authors: Alexis
authors: A
authors: Baratoff
authors: 1] SISSA, Via Bonomea 265, Trieste 34136, Italy [2] CNR-IOM Democritos National Simulation Center, Via Bonomea 265, Trieste I-34136, Italy [3] International Centre for Theoretical Physics (ICTP), PO Box 586, Trieste I-34014, Italy.
authors: Erio
authors: E
authors: Tosatti
authors: Department of Physics, University of Basel, Klingelbergstraße 82, Basel 4056, Switzerland.
authors: Ernst
authors: E
authors: Meyer