Epitaxial growth of ultrathin Cr films on Mo (110) at elevated temperature

Abstract

The principal details of Cr film growth on Mo 110 at elevated temperature are described. Cr films form nanostripes by the step-flow growth mechanism for film coverages up to 3 monolayers. In contrast to the Fe/Mo 110 system, there is no indication of strain relaxation in either the first, second, or third layers. The Cr nanostripes remain pseudomorphic up to the onset of Stranski-Krastanov growth, which is typified by the formation of nanowedge islands. This is accompanied by the formation of a two-dimensional dislocation network within the nanowedge islands. Two types of steps can be observed on top of the Cr nanowedges, unlike the Fe/Mo 110 system where the 110 surface of the Fe nanowedges is unbroken by any steps. The first are monatomic steps formed by incomplete Cr layers, while the second are fractional steps formed between adjacent layers with different degrees of tetragonal distortion. The fractional steps are modeled using the first principles calculations.