Surface structure 

The Sixth Int’l Conference on the Structure of Surfaces (ICSOS-6), held at the U. of British Columbia in July 1999, covered the atomic-level structure of solid surfaces, and the role of surface and interfacial structure in influencing the properties of technologically important materials. A special theme concerned surfaces of oxides of environmental interest, and invited speakers in this area included B. Kasemo (Chalmers U., Göteborg), G.E. Brown (Stanford U.), V.E. Henrich (Yale U.), S.A. Chambers (Pacific Northwest Nat. Lab) and M. Salmeron (Lawrence Berkeley Nat. Lab.).

Other prominent topics included metal surfaces, for which there were invited talks by B.S. Clausen (Haldor Topsøe Res. Lab., Denmark) on catalysis on nanoparticles, P.A. Thiel (U. Iowa and Ames Lab.) on quasicrystals, D. Menzel (Tech. Univ. München) on coadsorption structures, and B.A. Joyce (Imperial College, London) on surfaces of semiconductors, A.P. Hitchcock (McMaster U.) discussed passivation layers, and K. Akimoto (Nagoya U.) covered the use of surface X-ray diffraction (SXRD) to quantify strains at Si(111) surfaces. Invited talks on theory were given by K. Hermann (Fritz-Haber-Institut, Berlin) on transition oxide surfaces and J. Tersoff (IBM, Yorktown Heights) on structure of the Si-SiO₂ interface; other keynote talks were those of S. Ferrer (ESRF, Grenoble) on the use of SXRD to characterize ultrathin magnetic films, A. Atrei (U. Siena) on structure of semiconducting surfaces used as gas sensors, L.D. Marks (Northwestern U.) on direct methods for surface structure determination, and J. Gimzewski (IBM, Zürich) on designer molecules for fabricating nanoscaled machines. Applications of scanning tunneling microscopy (STM), low-energy electron diffraction (LEED), photoelectron diffraction and SXRD were prominent. Considerable progress is being made with the latter technique, including its use to probe structure at liquid-solid interfaces, and for giving new insight for adsorption systems with large unit mesh areas (H.L. Meyerheim, U. München).

The Surface Structure Prize, for outstanding achievement in the field of surface and interface structure, was awarded to K. Takayanagi for his quantitative determination of the atomic geometry of Si(111)-(7x7).” This is the single most important structure determination in all of surface science. It brought together fragmentary results from a host of other techniques into single coherent structure that has withstood the test of time and revealed the amazing complexity of new two-dimensional compounds formed at semiconductor surfaces. It resolved three decades of controversy about the structure. It was a ‘tour de force’ of experimental sample preparation and gave new insights into the energetics of semiconductors surface reconstructions, an amazing accomplishment of truly historic proportions. The ICSOS Young Scientist Prize was awarded to Peter Broekmann (U. of Bonn). ICSOS-7 will be held in 2002 at the U. of Newcastle, Australia.

K.A.R. Mitchell (Chair ICSOS-6), U.of British Columbia