The structure of a single step on the surface of a Kossel crystal in equilibrium: A Monte Carlo simulation

Abstract

Until now the equilibrium structure and properties of a monatomic step on a crystal surface have been described by statistical theories excluding overhanging ledge configurations and kink correlation. At higher temperatures the validity of these approximations is questionable. For these temperatures we have studied the (01) step of a (001) vicinal surface of a Kossel crystal using the Monte Carlo simulation technique for a one− and two−dimensional computer model. In our temperature region the ledge overhang density varies exponentially with ω according to h=29 exp(−5.8ω). The jump density distribution and the ledge roughness are in good agreement with statistical theories. There is no apparent kink correlation except a trivial one due to ledge overhangs. The ledge width originating from clustering at the ledge increases strongly with step length and temperature. For ω=1.0 it reaches a mean and maximal value of 7 and 40 units, respectively, for a step length of 960 units. With the help of modern techniques, these are visible dimensions.