title: Probing molecular dynamics at the nanoscale via an individual paramagnetic centre.
abstract: We demonstrate a protocol using individual nitrogen-vacancy centres in diamond to observe the time evolution of proton spins from organic molecules located a few nanometres from the diamond surface. The protocol records temporal correlations among the interacting protons, and thus is sensitive to the local dynamics via its impact on the nuclear spin relaxation and interaction with the nitrogen vacancy. We gather information on the nanoscale rotational and translational diffusion dynamics by analysing the time dependence of the nuclear magnetic resonance signal. Applying this technique to liquid and solid samples, we find evidence that liquid samples form a semi-solid layer of 1.5-nm thickness on the surface of diamond, where translational diffusion is suppressed while rotational diffusion remains present. Extensions of the present technique could be exploited to highlight the chemical composition of molecules tethered to the diamond surface or to investigate thermally or chemically activated dynamical processes such as molecular folding.
authors.affiliation: 3rd Physics Institute, University of Stuttgart, 70569 Stuttgart, Germany.|IQST, University of Stuttgart, 70569 Stuttgart, Germany.|Max Planck Institute for Solid State Research, 70174 Stuttgart, Germany.
authors.forename: T
authors.initials: T
authors.lastname: Staudacher
authors.affiliation: Department of Nuclear Solid State Physics, Institute for Experimental Physics II, University of Leipzig, Linnéstrasse 5, 04103 Leipzig, Germany.
authors.forename: N
authors.initials: N
authors.lastname: Raatz
authors.affiliation: Department of Nuclear Solid State Physics, Institute for Experimental Physics II, University of Leipzig, Linnéstrasse 5, 04103 Leipzig, Germany.
authors.forename: S
authors.initials: S
authors.lastname: Pezzagna
authors.affiliation: Department of Nuclear Solid State Physics, Institute for Experimental Physics II, University of Leipzig, Linnéstrasse 5, 04103 Leipzig, Germany.
authors.forename: J
authors.initials: J
authors.lastname: Meijer
authors.affiliation: 3rd Physics Institute, University of Stuttgart, 70569 Stuttgart, Germany.|IQST, University of Stuttgart, 70569 Stuttgart, Germany.|Walter Schottky Institut and Department of Physics, TUM-Technical University of Munich, Am Coulombwall 4, 85748 Garching, Germany.
authors.forename: F
authors.initials: F
authors.lastname: Reinhard
authors.affiliation: Department of Physics, CUNY-City College of New York, 160 Convent Avenue, New York, NY 10031, USA.
authors.forename: C A
authors.initials: CA
authors.lastname: Meriles
authors.affiliation: 3rd Physics Institute, University of Stuttgart, 70569 Stuttgart, Germany.|IQST, University of Stuttgart, 70569 Stuttgart, Germany.
authors.forename: J
authors.initials: J
authors.lastname: Wrachtrup