Calculated electronic structure of metallic multilayers formed by noble and transition metals

摘要

Full-potential Linearized Augmented Plane Wave calculations are performed to investigate the properties of the electronic charge of metallic multilayers formed by non-magnetic and magnetic elements (i.e. Ag, Cu and Fe). The multilayer structure is of the type A_n, A_nB_n or (AB)_n where A, B indicate Ag, Cu and Fe and n is the number of layers of the element A or B. The problem addressed by this study is the transition from the 2D behavior of the isolated monolayer to the 3D bulklike character. Therefore the calculations, carried out at paramagnetic level, illustrate the dependence of the density of states on the multilayer thickness and composition. For the three elements the main feature of the inter-layer coupling is the absence of charge intermixing and hybridization. For structures with a number of layers n ≤ 5 the density of states bandwidth has a decrease, with respect to the bulk value, approximately proportional to the reduced coordination. At the critical thickness n = 5 and above, a noticeable difference exists between the charge in the outer layers, with reduced coordination and bandwidth, and the central layers with a bulklike density of states. Averaging between these contributions leads to the re-installment of bulklike properties. These results are in essential agreement with analytical band theories and quantum mechanical calculations for similar systems and with experiments.