SurfaceScience21 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 93: Poster Session VII: Graphene and beyond I

O 93.7: Poster

Donnerstag, 4. März 2021, 10:30–12:30, P

hBN/Pt(111) and hBN/Ir(111): distinctive templates for Cs adsorption — •Jiaqi Cai, Robin Ohmann, and Carsten Busse — Department Physik, Universität Siegen, Walter-Flex-Str. 3, 57072 Siegen

High-quality two-dimensional materials (2DM) can be grown by epitaxial methods on the high-symmetry surfaces of transition metal crystals. This epitaxy leads to the interaction between 2DMs with the underlying substrate, which periodically modulates their geometric and electronic structure. This spatial periodicity constitutes a moiré pattern.

The periodic electronic modulation of the moiré pattern provides a template for adsorbates. To study this templating effect, we deposit Cs onto hBN/Pt(111) and hBN/Ir(111). Our scanning tunneling microscopy measurements reveal, hBN/Pt(111) and hBN/Ir(111) are very different templates: the preferred adsorption sites on hBN/Pt(111) are the strongly bonded regions (valleys) of the moiré unit cell, and on hBN/Ir(111) the weakly bonded regions (hills). Furthermore, one valley region on hBN/Pt(111) can accommodate multiple alkali metal atoms, while only one single Cs atom can adsorb on the hill of the hBN/Ir(111) moiré unit cell. An additional feature of Cs adsorption on hBN/Ir(111) is that there are two hill regions in one moiré unit cell. With the proper preparation procedure, the adsorbed Cs atoms form an unusual honeycomb lattice.