Abstract
A plateau-like surface structure was found on single crystals grown in tungsten wire. Plateaus were observed on the surface normal to the (110), (112), and (001) directions. A "shingle" structure was observed superimposed upon the plateaus. A wire subjected to only mild heat treatment showed both types of structure, indicating that evaporation cannot be the only mechanism involved. All wires were heated by ac exclusively to avoid the "dc etch."