Regensburg 2022 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 25: Focus Session: Atomic-Scale Characterization of Correlated Ground States in Epitaxial 2D Materials

O 25.6: Vortrag

Dienstag, 6. September 2022, 12:30–12:45, H2

Realization of Pb honeycomb stuctures by intercalation of buffer layers on SiC(0001) — •Chitran Ghosal, Markus Gruschwitz, and Christoph Tegenkamp — Institut für Physik, TU Chemnitz

The growth of 2D honeycomb lattices of group IV-elements has attracted a lot of interest during the last years. In contrast to graphene, the 2D analogues of Si and Ge can be stabilized on metals, while stanene and plumbene were recently prepared on compound crystals and magnetic substrates, respectively. Here we report on the intercalation of Pb using buffer layers (BL) on SiC(0001), resulting in the formation of freestanding and charge neutral graphene [1]. Depending on the bias voltage, scanning tunneling microscopy reveals complex Moiré structures, which are consistently explained in consideration of two plumbene lattices. These are rotated each by ±7.5^∘ with respect to graphene and, thus, are commensurate with the former 6√3× 6 √3 symmetry of the BL on SiC(0001). Locally, a (2× 2) pattern becomes visible in STM and is expected since the lattice constant of plumbene is twice as large as for graphene. Local spectroscopy (STS) done at 4 K reveals an electronic gap of 30 meV and is in qualitative agreement with the band structure of low-buckeled and charge-neutral plumbene.

[1] M. Gruschwitz et al., Materials 14, 7706 (2021)