Berlin 2018 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 96: Frontiers of Electronic-Structure Theory: Correlated Electron Materials VII (joint session O/TT/MM/DS/CPP)

TT 96.5: Vortrag

Donnerstag, 15. März 2018, 16:15–16:30, HL 001

Hubbard interactions from density-functional perturbation theory — •Iurii Timrov, Nicola Marzari, and Matteo Cococcioni — Theory and Simulation of Materials (THEOS), and NCCR-MARVEL, École Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland

DFT+U+V is a simple and powerful tool to model systems containing partially-filled manifolds of localized states. However, the Hubbard parameters are often - and in our view incorrectly - treated semi-empirically. Conceptual and practical methods to determine e.g. the Hubbard U parameter have nevertheless been introduced long ago, based either on the constrained random-phase approximation (cRPA) or on linear-response theory. However, these approaches are often overlooked due to their cost or complexity. Here, we introduce a computationally inexpensive and straightforward approach to determine on-site U and inter-site V, hitherto obtained from the difference between bare and self-consistent inverse electronic susceptibilities evaluated from supercell calculations. By recasting these calculations in the language of density-functional perturbation theory we remove the need of supercells, and allow for a fully automated determination of susceptibilities and Hubbard parameters. Such developments open the way for deployment in high-throughput studies, while providing the community with a simple tool to calculate consistent values of U and V for any system at hand.