Supporting information to ”Plastic de- formation of single nanometer-sized crystals”

Metal crystals were encapsulated in graphitic shells by evaporation of metal and carbon in an electric arc discharge [1–4]. Holes were drilled into the graphite cathodes and filled with a powder consisting of a mixture of graphite and a metal. Gold, platinum, molybdenum, or tungsten powders were used, respectively. An arc (40 V, 55 A) was operated for 510 seconds in a helium atmosphere (330 mbar). The deposit was scraped from on the cathodes and dispersed under sonication in ethanol and collected on Cu or Mo grids for TEM applications. The most relevant physical properties of the metals used in our experiments are listed in Table I, including stacking fault (SF) formation energy. The data are taken from Refs [5–7]. We stress that we observe fcc-Mo and W crystals in our experiment, but in Table I we refer to the theoretical shear stress in the bcc phase as given in the handbooks. We used these data because we are not aware of any experimental data for fcc-W or Mo. Although the numbers for fcc and bcc may not be exactly the same, we expect that the bcc data should nevertheless be relevant for qualitative estimates.