Regensburg 2019 – wissenschaftliches Programm

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MM: Fachverband Metall- und Materialphysik

MM 23: Methods in Computational Materials Modelling (methodological aspects, numerics)

MM 23.6: Vortrag

Mittwoch, 3. April 2019, 11:45–12:00, H44

Density-gradient-free variable in exchange-correlation functionals for detecting inhomogeneities in the electron density — •Fabien Tran and Peter Blaha — Vienna University of Technology, Vienna, Austria

A new type of approximation for the exchange and correlation functional in density functional theory is proposed. This approximation depends on a variable, u, that is able to detect inhomogeneities in the electron density ρ without using derivatives of ρ. Instead, u depends on the orbital energies which can also be used to measure how a system differs from the homogeneous electron gas. Starting from the functional of Perdew, Burke, and Ernzerhof (PBE) [Phys. Rev. Lett. 77, 3865 (1996)], a functional depending on u is constructed. Tests on the lattice constant, bulk modulus, and cohesive energy of solids show that this new u-dependent PBE-like functional is on average as accurate as the original PBE or its solid-state version PBEsol. Since u carries more nonlocality than the reduced density gradient s used in functionals of the generalized gradient approximation (GGA) like PBE and α used in meta-GGAs, it will be certainly useful for the future development of more accurate exchange-correlation functionals.