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TT: Fachverband Tiefe Temperaturen

TT 32: Focused Session: Frontiers of Electronic Structure Theory 3 (jointly with HL and O)

TT 32.5: Vortrag

Dienstag, 12. März 2013, 11:45–12:00, H36

Large-Scale Moiré Patterns of hexagonal Boron Nitride on Cu(111): DFT Studies of Structural and Electronic Properties — •Ralph Koitz, Ari P Seitsonen, Marcella Iannuzzi, and Jürg Hutter — Institute of Physical Chemistry, University of Zurich, Switzerland

Hexagonal boron nitride (h-BN) adsorbed on metal surfaces shows great promise for applications in nanoscience. Interesting structural and electronic properties have been found, e.g. for h-BN on Rh(111) and Ru(0001), where the overlayer is strongly corrugated. Recent experiments with h-BN on Cu(111) indicate that the difference in lattice constants and a rotation of the monolayer lead to moiré patterns with periodicities greater than 5 nm. To thoroughly understand this system, however, further insight is needed at the atomic level.

In this contribution we present an in-depth DFT study of a moiré pattern of a rotated 24×24 h-BN sheet on a 23×23 Cu(111) slab. The periodic pattern extends over 6 nm, making this simulation the largest of its kind so far reported. We study the gradual change of adsorption registry of the monolayer, and its influence on the electronic structure. Both B and N occupy the entire range of top, hcp, fcc, and bridging positions. This modulation over the unit cell is reflected in the projected DOS, the electrostatic potential, and the contrast in simulated STM images. Contrary to other h-BN/metal systems, only minute structural changes occur upon adsorption. Our results show that the observed corrugation is chiefly electronic in nature and strongly related to the lateral variation of adsorption registries.