Scanning tunneling microscopy observation of epitaxial bcc-Fe(001) surface

We report the first atomic-resolution scanning tunneling microscopy (STM) i mage of epitaxial bcc-Fe(001) films grown on MgO(001) substrates. A 50-Angs trom-thick Fe film grown at a growth temperature of 550K formed square pyra midal islands with atomically flat terraces. The terraces were found to ran ge between 5 nm and 20 nm in width separated by monoatomic high steps. The film exhibited a (1 x 1) unreconstructed structure at a film thickness belo w 19 Angstrom 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 x 2) struct ure.