In this Letter, we demonstrate that it is possible to form a two-dimensional (2D) silicene-like Si5Ge compound by replacing the Si atoms occupying on-top sites in the planar-like structure of epitaxial silicene on ZrB2(0001) by deposited Ge atoms. For coverages below 1/6 ML, the Ge deposition gives rise to a Si6−xGex alloy (with x between 0 and 1) in which the on-top sites are randomly occupied by Si or Ge atoms. The progressive increase of the valence band maximum with x observed experimentally originates from a selective charge transfer from Ge atoms to Si atoms. These achievements provide evidence for the possibility of engineering the bandgap in 2D SiGe alloys in a way that is similar for their bulk counterpart.
@article{arxiv.2003.04612,
title = {Bandgap engineering in an epitaxial two-dimensional honeycomb Si$_{6-x}$Ge$_x$ alloy},
author = {Antoine Fleurence and Yuto Awatani and Camille Huet and Frank B. Wiggers and Steaphan M. Wallace and Takahiro Yonezawa and Yukiko Yamada-Takamura},
journal= {arXiv preprint arXiv:2003.04612},
year = {2021}
}