Results from a LEED analysis of NiAl(110) demonstrate that it possesses a large rippled relaxation away from its hypothetical truncated bulk surface, with the Al sites of the top composite Ni-Al layer being displaced approximately 0.22 Å above the Ni sites. The evidence for this rippling is strong, since the agreement achieved between calculated and experimental $I-V$ profiles is of the same quality obtained in better LEED analyses of monatomic surfaces.

• Received 22 October 1984

DOI:https://doi.org/10.1103/PhysRevLett.54.566