IUVSTA 15th International Vacuum Congress (IVC-15), AVS 48th International Symposium (AVS-48), 11th International Conference on Solid Surfaces (ICSS-11)
    Surface Science Friday Sessions
       Session SS1-FrM

Paper SS1-FrM8
Surface Reconstruction STM Studies of Clean and Oxidized Low Index FeAl Surfaces

Friday, November 2, 2001, 10:40 am, Room 120

Session: Dynamics of Metal Surfaces
Presenter: O. Kizilkaya, Louisiana State University
Authors: O. Kizilkaya, Louisiana State University
D.A. Hite, Louisiana State University
D.M. Zehner, Oak Ridge National Laboratory
P.T. Sprunger, Louisiana State University
Correspondent: Click to Email
Details of the atomic reconstruction behavior of clean and oxidized (110), (210) and (310) surfaces of the ordered bimetallic alloy FeAl has been studied with STM. Prefentially sputtering impedes the aluminum concentration on the surfaces. Aluminum preferentially segregates to the surface layer upon sequential annealing of these low index surfaces. Depending on the annealing temperature, there are a sequence of differing surface reconstructions on FeAl(110). At 400 C, a bulk terminated surface is observed. Between the temperatures range of 400-600 C and 800-1000 C an incommensurate FeAl2 overlayer is obtained. At annealing temperatures of 600-800 C, STM images reveal a long-range missing row reconstruction parallel to the [001] direction. For a wide range of annealing temperatures, FeAl(210) reconstructs to a (1x3) structure. The surface has alternating (100) and (110) facets. A similar type of reconstruction is observed for FeAl(310); however, the surface is not stable but facets. The crystal miscuts and kinetic effects are the main reason for instability. In the case of oxidized FeAl(110), STM reveals the formation of a thin-film gamma-alumina at low coverages. This structure is characterized as a hexagonal moir@aa e@ pattern with a spot-spot distance of 1.8 nm. Research conducted at Oak Ridge National Laboratory, managed by UT-Battelle, LLC, for the U.S. Department of Energy, under contract DE-AC05-00OR22725. Research was supported by U.S. DOE contract No. DE-FG02-98ER45712.