Atomically accurate Si grating with 5.73 nm period

A vicinal surface of silicon is found that exhibits an atomically accurate step pattern with a period of 5.73 nm, corresponding to 17 atomic rows per (111) terrace. It can be viewed as reconstructed Si(557) surface, where a triple step is combined with a single Si(111)7×7 unit. The driving forces for establishing regular step patterns are discussed.