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DS: Fachverband Dünne Schichten

DS 39: Resistive Effects I

DS 39.1: Talk

Thursday, March 10, 2016, 09:30–09:45, H8

Investigation of oxygen vacancy formation and migration in HfO₂ from density functional theory — •Marta Gibertini, Daniel Wortmann, Gustav Bihlmayer, and Stefan Blügel — Peter Grünberg Institut (PGI-1) and Institute for Advanced Simulation (IAS-1), Forschungszentrum Jülich GmbH and JARA, D-52425 Jülich, Germany

Oxygen vacancies are crucial in the performance of resistive random access memory (ReRAM), one of the most promising device concepts for nonvolatile memory. However, the exact mechanism of switching of a ReRAMs between two states (low and high resistance) is still not clear, especially at the microscopic level. In the formation process of conductive pathways, the vacancy formation and migration play an important role. Therefore, we present a density functional theory (DFT) study of the formation energy and the diffusion barrier of oxygen vacancies in HfO₂. Different structures (cubic, tetragonal, monoclinic), different charge states of the vacancy and different pathways are considered. The role of electronic correlations is investigated in the DFT+U model. The calculations are done for different supercell sizes employing the electronic structure code juRS, a real-space finite-difference implementation of the projector augmented wave (PAW) method.