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RESEARCH PRODUCT

Monte Carlo Simulations of Surfaces and Interfaces in Materials

subject

description

Many applications of materials are controlled by their surface and interface properties. In particular, metallic alloys (but also mixed dielectric materials and amorphous polymer blends) are not homogeneously mixed on a microscopic length scale, although they are macroscopically homogeneous. Depending on the preparation of the sample, there exists a heterophase microstructure, with typical domain sizes, e.g. in the 1 to 102 µm range, separated by interfaces between them. The physical properties of such intrinsic interfaces (grain boundaries between small crystallites, antiphase domain boundaries in ordered alloys, Bloch walls in magnetic materials, etc.) are not only an important controlling factor for many properties, but also a challenging fundamental problem of condensed matter science. The same fact is true for external surfaces of materials, e.g. a surface of a metallic alloy against vacuum or air, or a surface of a fluid mixture against the wall of a container, etc.: there may exist either a microscopic layer (thickness about 1 nm) where composition and structure differ significantly from the bulk (e.g., surface enrichment or surface induced disordering in alloys), or even mesocopic wetting layers (thickness 10-102 nm) may form.