Dresden 2020 – scientific programme
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O: Fachverband Oberflächenphysik
O 47: Poster Session - 2D Materials: Electronic Structure, Excitations, etc.
O 47.7: Poster
Tuesday, March 17, 2020, 18:15–20:00, P2/EG
p Orbital flat band and Dirac cone in the electronic honeycomb lattice — •Thomas Gardenier1, Jette van den Broeke2, Jesper Moes1, Ingmar Swart1, Christophe Delarue3, Marlou Slot1, Cristiane Morais Smith2, and Daniel Vanmaekelbergh1 — 1Debye Institute for Nanomaterials Science, Utrecht University, The Netherlands — 2Institute for Theoretical Physics, Utrecht University, The Netherlands — 3Université de Lille, CNRS, Centrale Lille, Yncréa-ISEN, Université Polytechnique Hauts-de-France, UMR 8520 - IEMN, F-59000 Lille, France
Honeycomb systems have generated much interest in experimental and theoretical physics due to their interesting band structures. The architypical example of a honeycomb lattice is graphene. The electronic structure of graphene close to the Fermi level can be understood by only considering C 2pz orbitals. Bands due to coupling of sp2 hybrid orbitals are either much higher or lower in energy. It has been shown that in the absence of hybridisation, the band structure of honeycomb lattices features a topologically non-trivial flat band, as well as Dirac cones formed by px and py orbitals.
We patterned a Cu(111) surface with CO molecules to confine the surface state electrons into a honeycomb geometry. By careful tuning of the lattice parameters, we created a honeycomb lattice where s- and p-orbital bands are separated. Scanning tunneling spectroscopy and wavefunction mapping are used to determine the band structure and visualise the electron densities. The results are complemented by theoretical muffin-tin and tight-binding calculations.