An XPD and LEED study of highly strained ultrathin Ni films on Pd(1 0 0)

The epitaxial growth of ultrathin Ni films on the Pd(1 0 0) surface was studied by means of X-ray photoelectron diffraction (XPD) and LEED experiments. In excellent numerical agreement with the predictions of elasticity theory, the data indicate the formation of tetragonally strained Ni epitaxial layers, which subsequently turns into a bulk-like Ni structure as the thickness of approximately 12 MLE is exceeded. This study demonstrates that LEED and XPD methodologies are rather complementary in order to have a detailed picture of the evolution of the overlayer structure in different thickness regimes.