Crystal perfection by strain engineering: The case of Fe/V (001)

We study the effect of bilayer thickness at fixed volume fraction on the structural quality of Fe/V (001) superlattices. We find that such artificial metallic superlattices can be manufactured with excellent crystal quality and layering up to at least 50 Å in repeat distance (Λ = LFe + LV). For an intended fixed ratio of the constituents: LFe/LV= 1/7, out-of-plane coherence lengths comparable to the thicknesses of the samples were obtained. We evaluate the strain in- and out-of-plane of both layers as a function of the bilayer thickness and comment on the growth using the framework of linear elasticity theory. We interpret the stability of the superlattice against crystal degradation due to the alternating compressive and tensile strain, yielding close to ideal lattice matching to the substrate.