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O: Fachverband Oberflächenphysik
O 2: Focussed session: Theory and computation of electronic structure: new frontiers I (jointly with HL, DS)
O 2.5: Vortrag
Montag, 14. März 2011, 12:30–12:45, TRE Phy
AuN clusters (N=1-6) supported on MgO(100) surfaces: the effect of exact exchange and dispersion interactions on adhesion energies. — •Lauro Oliver Paz-Borbón1, Giovanni Barcaro2, Alessandro Fortunelli2, Sergey Levchenko1, and Matthias Scheffler1 — 1Fritz Haber Institut der Max Planck Gesellschaft, Berlin. — 2Istituto per i Processi Chimico-Fisici del Consiglio Nazionale delle Ricerche, Pisa.
Understanding the interaction between a metal nanoparticle and an oxide surface is a prerequisite for further development of nanocatalysts displaying tailor-made properties. In this work, we study the interaction of an Au adatom and AuN clusters (N=2-6) supported on pristine and defected MgO(100) surfaces, using a DFT all-electron full-potential approach [1], under a hierarchy of exchange-correlation (XC) functional approximations: ranging from the generalized gradient approximation (PBE and RPBE) to hybrid functionals (PBE0, HSE06) and exact exchange (EX) plus correlation in the random phase approximation (EX-cRPA/cRPA+). Our results for the Au adatom at the oxygen site show that, by reducing the self-interaction error (SIE) through the inclusion of EX, smaller adhesion energies values are found when compared to those calculated using hybrid and semi-local functionals; concurrently, the diffusion energy barrier increases. Dispersion interactions [2] are found to play a crucial role in determining the energetics of AuN clusters. [1] Blum, V. et al., Computer Physics Communications 2009, 2175, 180. [2] Tkatchenko, A., Scheffler, M., Phys. Rev. Lett. 2009, 102, 073005.