Fabrication and characterization of strain-driven self-assembled CrN nanoislands on Cu(001)

Abstract

Two types of square-shaped self-assembled CrN nanoislands of monoatomic layer are fabricated on the Cu(001) substrate. The island edges are commonly oriented along the ⟨110⟩ directions, and the islands locally form a two-dimensional square superstructure. The mean height is either 0.09 or 0.18 nm, and the average lateral size of the islands is 2.5 × 2.5 nm2 for the lower islands and 3.5 × 3.5 nm2 for the others. The formation of the higher CrN islands is attributed to an unconventional short-range attractive mechanism. The lower islands coexisting with the clean surface are made by the interplay between the long- and short-range interactions.