Abstract:

In this talk, I will introduce a robust semi-empirical Hamiltonian for large-scale simulations of complex nanostructures developed by the condensed mater theory group at University of Louisville. The Hamiltonian, referred as self-consistent (SC) and environment-dependent (ED) Hamiltonian, is developed in the framework of linear combination of atomic orbitals (LCAO) and includes multi-center electron-ion and electron-electron interactions. Linear scaling and parallel algorithms for large-scale simulations of materials have also been incorporated. The present approach goes beyond the traditional two-center tight-binding Hamiltonians in terms of its accuracy and transferability and allows the study of system sizes that are beyond the scope of ab-initio simulations. We have studied a wide-variety of complex materials and complex phenomena using the SCED-LCAO approach. I will present some of our recent results in this talk including (i) the phase transformations of carbon clusters upon annealing, (ii) the bucky-diamond structure of SiC clusters, and (iii) the morphology and stability of SiC nanowires. The successful outcome of these case studies is a testament to the transferability and the predictive power of the Hamiltonian to different types of atomic environments (i.e., co-ordinations and bonding configurations).
 
 
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