The excess of surface dangling bonds makes the formation of free-standing two-dimensional (2D) metals unstable and hence difficult to achieve. To date, only a few reports have demonstrated 2D metal formation over substrates. Here, we show a free-standing crystalline single-atom-thick layer of iron (Fe) using in situ low-voltage aberration-corrected transmission electron microscopy and supporting image simulations. First-principles calculations confirm enhanced magnetic properties for single-atom-thick 2D Fe membranes. This work could pave the way for new 2D structures to be formed in graphene membranes.
Zhao, J., Deng, Q., Bachmatiuk, A., Sandeep, G., Popov, A., Eckert, J., & Rümmeli, M. H. (2014). Free-standing single-atom-thick iron membranes suspended in graphene pores. Science, 343(6176), 1228-1232. https://doi.org/10.1126/science.1245273