Berlin 2018 – scientific programme

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DS: Fachverband Dünne Schichten

DS 10: Oxide Semiconductors for Novel Devices (Focussed Session): Session II

DS 10.6: Talk

Monday, March 12, 2018, 16:15–16:30, E 020

Ab initio study of oxygen vacancy formation and migration in HfO₂ under electric field — •Marta Gibertini, Daniel Wortmann, Gustav Bihlmayer, Shigeru Tsukamoto, and Stefan Blügel — Peter Grünberg Institut and Institute for Advanced Simulation, Forschungszentrum Jülich and JARA, D-52425 Jülich, Germany

Among the storage devices investigated so far, resistive random access memories (ReRAMs) stand out because of the high-speed/high-density properties and the low energy required for the writing/rewriting circles. A deep understanding of the role played by point defects and dopants is important for an optimization of the device functionality. We present a density functional theory (DFT) study aimed at investigating the formation energies and the migration energy barriers of oxygen vacancies in monoclinic HfO₂. We look at the dependence of these properties in bulk and film systems on the magnitude of an external electric field. We also study the influence of Yttrium dopants on the diffusion. The nudged elastic band method is applied and the DFT calculations are performed with the electronic structure code jüRS, a real-space finite-difference implementation of the projector augmented wave (PAW) method. The real-space formalism is chosen because it allows a flexible treatment of the boundary conditions, and therefore, it is favourable for the application of an external electric field in terms of a capacitor model. - The work is supported by DFG - SFB 917 (Nanoswitches)