title: Isotope analysis in the transmission electron microscope.
abstract: The Ångström-sized probe of the scanning transmission electron microscope can visualize and collect spectra from single atoms. This can unambiguously resolve the chemical structure of materials, but not their isotopic composition. Here we differentiate between two isotopes of the same element by quantifying how likely the energetic imaging electrons are to eject atoms. First, we measure the displacement probability in graphene grown from either12C or13C and describe the process using a quantum mechanical model of lattice vibrations coupled with density functional theory simulations. We then test our spatial resolution in a mixed sample by ejecting individual atoms from nanoscale areas spanning an interface region that is far from atomically sharp, mapping the isotope concentration with a precision better than 20%. Although we use a scanning instrument, our method may be applicable to any atomic resolution transmission electron microscope and to other low-dimensional materials.
authors.affiliation: Faculty of Physics, University of Vienna, Faculty of Physics, Boltzmanngasse 5, 1090 Vienna, Austria.
authors.forename: Toma
authors.identifier: 0000-0003-2513-573X
authors.initials: T
authors.lastname: Susi
authors.affiliation: Faculty of Physics, University of Vienna, Faculty of Physics, Boltzmanngasse 5, 1090 Vienna, Austria.
authors.forename: Christoph
authors.initials: C
authors.lastname: Hofer
authors.affiliation: Faculty of Physics, University of Vienna, Faculty of Physics, Boltzmanngasse 5, 1090 Vienna, Austria.
authors.forename: Giacomo
authors.initials: G
authors.lastname: Argentero
authors.affiliation: Faculty of Physics, University of Vienna, Faculty of Physics, Boltzmanngasse 5, 1090 Vienna, Austria.
authors.forename: Gregor T
authors.initials: GT
authors.lastname: Leuthner
authors.affiliation: Faculty of Physics, University of Vienna, Faculty of Physics, Boltzmanngasse 5, 1090 Vienna, Austria.
authors.forename: Timothy J
authors.initials: TJ
authors.lastname: Pennycook
authors.affiliation: Faculty of Physics, University of Vienna, Faculty of Physics, Boltzmanngasse 5, 1090 Vienna, Austria.
authors.forename: Clemens
authors.initials: C
authors.lastname: Mangler
authors.affiliation: Faculty of Physics, University of Vienna, Faculty of Physics, Boltzmanngasse 5, 1090 Vienna, Austria.
authors.forename: Jannik C
authors.initials: JC
authors.lastname: Meyer
authors.affiliation: Faculty of Physics, University of Vienna, Faculty of Physics, Boltzmanngasse 5, 1090 Vienna, Austria.
authors.forename: Jani
authors.identifier: 0000-0002-1301-5266
authors.initials: J
authors.lastname: Kotakoski