We have observed for the first time two Tamm-type surface states on th
e (001) and (100) surfaces of equi-atomic CuAu I, at binding energies
of about 1.5 eV and 6.2 eV. By measuring their dispersions in k(parall
el to)-space we have located symmetry points in the surface Brillouin
zones, which has enabled us to deduce the lattice spacings in the surf
ace layer. We find that these values are very similar to those of the
bulk. Copyright (C) 1996 Elsevier Science Ltd.