Nonequilibrium Interface Dynamics:
Hierarchical Modeling and Multiscale Simulation of Materials Interfaces

CSIC Building (#406), Seminar Room 4122.
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Tight-binding Methodologies for Efficient Electronic Structure

Dr. Dimitrios Papaconstantopoulos

Center for Computational Materials Science at Naval Research Laboratory

Abstract:   Quantum mechanically accurate first-principles calculations for real materials are computationally limited to no more than 100-1000 atoms depending on the method used. Atomistic potentials methods can handle much larger systems but their results are often limited to just reproducing the database to which they are fitted. Tight-binding (TB) methods operate between these two extremes. In the TB methods the quantum mechanical behavior of the electrons is maintained, but the computational effort is much less than needed for first-principles calculations of comparable size. This talk describes the NRL Tight-Binding Method (NRL-TB), which maps the results of a limited set of first-principles calculations to a two-center non-orthogonal Slater-Koster TB Hamiltonian. The on-site Hamiltonian parameters are sensitive to the local environment and the hopping parameters are bond-length dependent. The method has been shown to successfully determine elastic constants, phonon frequencies, vacancy formation energies, and surface energies. In addition,TB molecular dynamics simulations are used to study mean square displacements and thermal expansion. We will discuss applications to spin-polarized systems, and multi-component systems, such as the newly discovered superconductor MgB2, semiconductor compounds (SiC), transition-metal carbides and aluminides, and ferroelectric materials such as PbZrO3.