Sc-Si multilayers are suggested as high-reflectivity coatings for a VUV interval of 35-50 nm. Fabricated mirrors show normal-incidence reflectivity of 30-54%, which is high enough for effective manipulation of the beams of compact-discharge, laser-driven x-ray lasers. The values obtained are not, however, limits for Sc-Si coatings. Theoretical estimations as well as electron microscopy studies of Sc-Si interfaces indicate a large potential for a further increase in their reflectivity.

The formation of interlayer transition zones (ITZs) in sputtered Mo/Si multilayer structures was studied by means of cross-section electron microscopy and grazing incidence reflectivity measurements. For the evaluation and calculation of interface effects the multiperiodic design of Mo/Si structure was used. It was found that the thickness asymmetry of ITZs (Mo-on-Si and Si-on-Mo) in Mo/Si multilayer structures depends on the degree of perfection of the crystalline structure of the molybdenum layer. A transition from asymmetrical to symmetrical ITZs with a disordering of the molybdenum crystalline structure was shown. A model for the formation mechanism of asymmetrical ITZs at the different interfaces in Mo/Si multilayer structures is suggested. According to this model, ITZ formation at the Mo-on-Si interface is controlled by the surface diffusion of Si atoms on the growing molybdenum surface. In contrast, ITZ formation at the Si-on-Mo interface is determined by the bulk diffusion of Si atoms in textured molybdenum grain

Novel superconducting superlattices with transition temperature in the range 2.5-6.4 K consisting only of semiconducting materials are discovered. Among them there are multilayers, including a wide-gap semiconductor as one of the components. It is shown that superconductivity is connected with the interfaces between two semiconductors containing regular grids of the misfit dislocations. The possibility of the dislocation-induced superconductivity is discussed.

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