The electron microscopy work was supported by the EPSRC (UK). SuperSTEM Laboratory is the EPSRC National Research Facility for Advanced Electron Microscopy. The authors would like to thank Prof. Lian Li (West Virginia University) for the provision of the specimen, as well as Hitachi High Technologies, and Orsay Physics and Tescan, for the preparation of FIB lamellae. MB is grateful to the SuperSTEM Laboratory for microscope access, and to the School of Chemical and Process Engineering at the University of Leeds for a visiting associate professorship and financial support. ME and SL acknowledge funding from the Austrian Science Fund (FWF) under grant nr. I4309-N36.
Google Scholar