Atomic Roughness of an Intrinsically Chiral Surface Orientation of an fcc Metal: Cu{531}

Intrinsically chiral metal surfaces would potentially offer a route toward enantioselective heterogeneous catalysis. A bulk-terminated {531} surface of an fcc metal has an intrinsically chiral unit mesh: it thus appears to be an attractive candidate for fundamental studies of the interaction of such an intrinsically chiral metal surface with chiral adsorbates. Using atomically resolved scanning tunnelling microscopy at 77 K, we show that the real Cu{531} surface departs strongly from ideal bulk termination, exhibiting a high degree of atomic-scale roughness. We examine the impact of the roughness on the low-energy electron diffraction pattern, discuss the origins and nature of the roughness in the context of thermal roughening, and comment upon the implications of the roughness for adsorption of chiral molecules.