Competition between surface reaction and diffusion of gold deposited onto ZrTe3

Surface reaction and diffusion of gold, deposited onto the (0 0 1) ZrTe3 van der Waals (vdW) surface, is studied by transmission electron and scanning tunneling microscopy. It is shown that both processes compete at temperatures as low as room temperature. In case of diffusion the deposited gold mostly disappears from the surface and intercalates into the vdW gaps of the substrate. Residual unreacted gold agglomerates are rather mobile and are often displaced by the scanning tip along the [1 0 0] direction of the substrate. In case of reaction, which usually takes place at somewhat higher substrate temperatures, grains of Zr3Te2, AuTe2 and/or Au2Te3 are formed. Contrary to unreacted gold, the reaction products are not mobile.