Atomic structure of thin dysprosium-silicide layers on Si(1 1 1)

We report on scanning tunneling microscopy results of thin dysprosium-silicide layers formed on Si(1 1 1). In the submonolayer regime, both a 2 3 × 2 3 R 30 ° and a 5 × 2 superstructure were found. Based on images taken at different tunneling conditions, a structure model could be developed for the 2 3 × 2 3 R 30 ° superstructure. For one monolayer, a 1 × 1 superstructure based on hexagonal DySi2 was observed, while several monolayers thick films are characterized by a 3 × 3 R 30 ° superstructure from Dy3Si5.