Extended X-ray absorption fine structure investigation of the structure of iron overlayers on Cu(111)

Abstract

Surface extended X-ray absorption fine structure (SEXAFS) has been used to probe the structure of ultrathin films of iron on Cu(111). With increasing film thickness, the interatomic separation falls from 2.57 angstroms rapidly towards that of bulk iron (2.48 angstroms). The degree of order and coordination in the films also fall over this region. These changes are consistent with a loss of face-centred cubic structure. However, the structure does not exhibit a clear body-centred cubic SEXAFS fingerprint until around eight layers.