Regensburg 2025 – scientific programme

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O: Fachverband Oberflächenphysik

O 61: 2D Materials: Electronic Structure and Exitations II (joint session O/HL/TT)

O 61.7: Talk

Wednesday, March 19, 2025, 12:15–12:30, H11

Two-dimensional breathing Kagome lattice of antimony atoms on a SiC substrate — •Bing Liu¹, Kyungchan Lee¹, Jonas Erhardt¹, Manish Verma¹, Stefan Enyner¹, Cedric Schmitt¹, Philipp Kessler¹, Lukas Gehrig¹, Chris Jozwiak², Aaron Bostwick², Martin Kamp¹, Eli Rotenberg², Jörg Schäfer¹, Simon Moser¹, Giorgio Sangiovanni¹, and Ralph Claessen¹ — ¹Physikalisches Institut, Universität Würzburg, 97074 Würzburg, Germany — ²Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA

The Kagome lattice, characterized by flat electronic bands, which represents a class of candidate materials for charge order, time-reversal symmetry-breaking and exotic superconductivity. In this work, we report the successful synthesis of a breathing Kagome lattice of Sb on SiC surface. Band mapping reveals a significant gap opening at the K point near the Fermi level, driven by different hopping parameters within the breathing Kagome lattice. Scanning tunneling microscopy measurements of this phase confirm a well-ordered 2x2 lattice reconstruction, consistent with the breathing Kagome unit cell. Furthermore, DFT calculations elucidate the role of the Sb p-orbitals. Specifically, near the Fermi level the physics is dominated by px and py orbitals, which are sensitive to hopping and possibly electron correlation, giving rise to an energy gap, and by their splitting reflect the breathing Kagome lattice situation. Our findings demonstrate a pathway for constructing two-dimensional Kagome lattices on semiconductor surfaces, and are encouraging further research into their spin and electronic properties.

Keywords: Breathing Kagome; Antimony; Flat band; Gap oppening; p-orbitals