Designing square two-dimensional gold and platinum

Square atomic configurations of two-dimensional gold and platinum are designed on the basis of density functional theory calculations. Calculations reveal that Au₉ and Pt₉ clusters form energetically stable perfect square structures. Combining and alternating two Au₉ and two Pt₉ allows for the formation of infinite square two-dimensional sheets of Au₉, Pt₉, and Au₁₈Pt₁₈. The electronic density of state reveals that two-dimensional Au₉, Pt₉, and Au₁₈Pt₁₈ retain metallic characteristics whereas two-dimensional Pt₉ and Au₁₈Pt₁₈ also possess magnetic properties. In addition, the multilayered two-dimensional Au₉ and Au₁₈Pt₁₈ of up to five layers and four layers, respectively, are designed. Two dimensional Au₉, Pt₉, and Au₁₈Pt₁₈ could have potential applications toward filtering gases or impurities in liquids as well as electronics.