  Surface alloying is a straightforward route to control and modify the
structure and electronic properties of surfaces. Here, We present a
systematical study on the structural and electronic properties of three novel
rare earth-based intermetallic compounds, namely ReAu2 (Re = Tb, Ho, and Er),
on Au(111) via directly depositing rare-earth metals onto the hot Au(111)
surface. Scanning tunneling microscopy/spectroscopy measurements reveal the
very similar atomic structures and electronic properties, e.g. electronic
states, and surface work functions, for all these intermetallic compound
systems due to the physical and chemical similarities between these rare earth
elements. Further, these electronic properties are periodically modulated by
the moir\'e structures caused by the lattice mismatches between ReAu2 and
Au(111). These periodically modulated surfaces could serve as templates for the
self-assembly of nanostructures. Besides, these two-dimensional rare
earth-based intermetallic compounds provide platforms to investigate the rare
earth related catalysis, magnetisms, etc., in the lower dimensions.
