Eva Olsson

Chalmers University of Technology, Department of Physics, Gothenburg, Sweden

Strain engineering can be used to tune the properties of advanced materials. Catalytic activity of metal nanoparticles and electrical properties of semiconducting nanowires are examples of structures where the strain induced effects have a strong influence on the performance in applications. We are using high resolution annular dark field (ADF) scanning transmission electron microscopy (STEM) imaging to obtain high resolution (better than 1 Å) and high precision (better than 1 pm) information about the local atomic structure [1]. We use in situ microscopy to perform electrical conductivity and nanoscale mechanical strain measurements using and electromechanical setup. We use also STEM combined with nanobeam electron diffraction to quantitatively evaluate the nanoscale strain distribution [2]. In addition, we have studied electric field induced changes on the atomic scale using in situ microscopy [3]. New aspects of material properties and mechanisms, not obvious from measurements on the macro scale are revealed using in-situ electron microscopy where interfaces and defects affect the material properties on the macro, micro, nano and atomic scale. The knowledge is crucial for not only the understanding of the mechanisms that are involved but also for the design or materials and devices with tailored properties.

[1] T. Nilsson Pingel, M. Jørgensen, A.B. Yankovich, H. Grönbeck and E. Olsson, “Influence of atomic site-specific strain on catalytic activity of supported nanoparticles”,Nature Communications 2018, https://doi.org/10.1038/s41467-018-05055-1.

[2] L. J. Zeng, C. Gammer, B. Ozdol, T. Nordqvist, J. Nygård, P. Krogstrup, A.M. Minor, W. Jäger and E. Olsson, ”Correlation between electrical transport and nanoscale strain in InAs/In0.6Ga0.4As core-shell nanowires, Nano Letters 2018, https://doi.org/10.1021/acs.nanolett.8b01782.

[3] L. de Knoop, M. J. Kuisma, J. Löfgren, K. Lodewijks, M. Thuvander, P. Erhart, A. Dmitriev and E. Olsson, “Electric-field-controlled reversible order-disorder switching of metal tip surface”, accepted for publication in Physical Review Materials July 2018.