Free-standing 2D metals from binary metal alloys

Abstract

Recent experiments have demonstrated the formation of free-standing Au monolayers by exposing the Au-Ag alloy to electron beam irradiation. Inspired by this discovery, we used semi-empirical effective medium theory simulations to investigate monolayer formation in 30 different binary metal alloys composed of late d-series metals such as Ni, Cu, Pd, Ag, Pt, and Au. In qualitative agreement with the experiment, we find that the beam energy required to dealloy Ag atoms from the Au-Ag alloy is smaller than the energy required to break the dealloyed Au monolayer. Our simulations suggest that a similar method could also be used to form Au monolayers from the Au-Cu alloy and Pt monolayers from Pt-Cu, Pt-Ni, and Pt-Pd alloys.