Scanning Tunneling Microscopy Observation of Epitaxial bcc-Fe(001) Surface

Abstract

We report the first atomic-resolution scanning tunneling microscopy (STM) image of epitaxial bcc-Fe(001) films grown on MgO(001) substrates. A 50-Å-thick Fe film grown at a growth temperature of 550 K formed square pyramidal islands with atomically flat terraces. The terraces were found to range between 5 nm and 20 nm in width separated by monoatomic high steps. The film exhibited a (1×1) unreconstructed structure at a film thickness below 19 Å; however, a reconstructed surface was found on thicker films. The atomic-resolution STM image and low energy electron diffraction (LEED) observation indicated that the reconstructed structure is a c(2×2) structure.