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O: Fachverband Oberflächenphysik

O 67: Electronic Structure Theory: General, Method Development

O 67.2: Poster

Mittwoch, 18. März 2015, 18:15–21:00, Poster A

SEMT: An Orthogonal and Localized Basis-Set for All-electron Density Functional Theory — •Andrea Nobile and Stefan Blügel — Peter Grünberg Institute (PGI-1) and Institute for Advanced Simulation (IAS-1), Forschungszentrum Jülich GmbH and JARA, Jülich, Germany

Employing all-electron methods for simulations by density functional theory (DFT) allows for unbiased, highly accurate solutions of the Kohn-Sham equations. Current popular all-electron schemes like FLAPW+LO and APW+LO use a basis set that is not localized in real space and as a consequence the resulting Hamiltonian is dense. These basis sets are non-orthogonal thereby posing constraints on the choice of the eigensolver and on the usage and development of alternative, less than cubic scaling convergence schemes.

We tackle the localization and orthogonality problem by combining spectral elements with muffin-tin spheres. The introduced method, that we call spectral-element-muffin-tin (SEMT), produces a basis set that is localized and numerically orthogonal by construction.

When compared to pure spectral element methods, our basis needs a substantially smaller number of degrees of freedom per atom. The strength of the SEMT method is in the combination of all-electron, real space, sparsity and orthogonality. We demonstrate the method with our implementation (Velvet) on some elemental materials by comparing the results with FLAPW+LO calculations.