Experimental Evidence for Epitaxial Silicene on Diboride Thin Films

As the Si counterpart of graphene, silicene may be defined as an at least partially sp(2)-hybridized, atom-thick honeycomb layer of Si that possesses pi-electronic bands. Here we show that two-dimensional, epitaxial silicene forms through surface segregation on zirconium diboride thin films grown on Si wafers. A particular buckling of silicene induced by the epitaxial relationship with the diboride surface leads to a direct pi-electronic band gap at the Gamma point. These results demonstrate that the buckling and thus the electronic properties of silicene are modified by epitaxial strain.