Functional Properties of Materials at Nano-scale: First-principles Theory

Materials exhibit a remarkable diversity in their properties, which are determined fundamentally by their electronic and atomic structure, and involve processes that occur at many length, energy and time-scales. As a result, these properties evolve in interesting manner as the size of a material is reduced to nano-scale. As most modern technologically important materials (from semiconductors to structural materials used in jet engines) are nano-structured, it is important to understand how their specific functional properties depend on size and structure. In this talk, we will first introduce a "standard model" of materials that allows prediction of their structure and properties with no empirical knowledge in principle. Deriving a material-specific model with input from this first-principles microscopic description and analyzing it with Monte Carlo or Molecular Dynamics simulations, we determine its multi-scale behavior. In particular, we show how functional properties like ferroelectricity in oxides, superconductivity in Ta, and mechanical behavior of metals evolve from their bulk to nano-scale form. The mechanisms uncovered through such theoretical analysis can be very valuable in design and prediction of novel materials and technologies.