When 10:30 AM - 11:30 AM Mar 30, 2018
Where 1670 Beyster
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Visualizing and Shaping the Nanoworld: From the Quantitative Interrogation of Site- and Species-Specific Interactions of Atoms to the Millimeter-Scale Engineering of Structures with Angstrom Precision

Professor Udo Schwarz
Yale University, Departments of Mechanical Engineering & Materials Science and Chemical & Environmental Engineering

The interactions a material exhibits with the environment are largely determined by the properties of the material’s surfaces. In the first part of this talk, we describe recent efforts to characterize a surface’s structure by enabling species-specific atomic resolution imaging and quantify chemical interaction strengths in three dimensions with picometer and piconewton resolution using noncontact atomic force microscopy [1-3] and outline how this information can be combined with local electronic information [4, 5]. Applications to explore topics such as surface chemistry or the atomic origins of friction will be presented for various model systems including oxides, metals, ionic crystals, and layered materials, with the ultimate goal to obtain a complete toolbox for the single-molecule characterization of surface reactions.

In the second part of the talk, we will then expand on the theme of atomic-scale manipulation by asking how surface morphologies of samples as large as multiple mm2 can be shaped at will with Angstrom precision. Here we demonstrate the imprinting of atomic step edges of a SrTiO3 single crystal used as mold into a Pt-based bulk metallic glass (BMG). Systematic studies revealed that (i) terraces on the BMG replicas possess atomic smoothness, (ii) the same mold can be used multiple times without degradation of mold or replicas, and (iii) the atomic-scale features on as-imprinted BMG surfaces have impressive long-term stability (years), thereby opening the possibility to induce surface properties by imprinting appropriate atomically defined surface morphologies.

[1]    B. J. Albers et al., Nature Nanotechnology 4, 307 (2009).

[2]    M. Z. Baykara et al., Advanced Materials 22, 2838 (2010).

[3]    O. E. Dagdeviren et al, Nanotechnology 27, 065703 (2016).

[4]    M. Z. Baykara et al., Physical Review B 87, 155414 (2013).

[4]    H. Mönig et al., ACS Nano 7, 10233 (2013).

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