The problem with experimentally creating 1D systems based on surface reconstructions is that usually due to the symmetry of the surface there are a few equivalent directions on the surface along which the reconstructions can form. On the figure below an example is shown of a surface with 3 such equivalent directions; 1 desirable one (marked by green lines) and 2 undesirable ones (marked by red lines).
The way that steps can be helpful in such situation is that because of their presence formation of reconstruction rows or chains will be enhanced in the direction along the steps and inhibited along the other two directions. Essentially steps on a well prepared stepped surface run along the same direction, making this direction a preferential one for formation of any structures. This way truly single domain over macroscopic areas surface reconstructions can be obtained (see links on the main 1D Surface Structures page for examples).
