Berlin 2018 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe
O: Fachverband Oberflächenphysik
O 48: Poster: 2D Materials beyond Graphene: TMDCs, Silicene and Relatives
O 48.5: Poster
Dienstag, 13. März 2018, 18:15–20:30, Poster A
Electron Lattice Discretization in Two-Dimensional Hexagonal Flat Band Systems — •Maximilian Uhl1, 2 and Wolfgang Häusler1 — 1Institut für Physik, Universität Augsburg — 2Present Adress: Max-Planck-Institut für Festkörperforschung, Stuttgart
The T3-lattice is a two-dimensional hexagonal lattice where jumps between certain lattice sites are suppressed by destructive quantum interference [2]. It features interesting properties such as a flat band where the electron single particle energies are constantly zero. Owing to Coulomb interactions, the electrons form Wigner crystals in the ground state. However, due to localization to specific lattice sites, perfect Wigner crystals can only be formed at commensurability with the underlying T3-lattice, requiring specific discrete electron densities [1]. Then, the system is insulating. At other electron densities, the extra carriers may contribute to a nonzero conductance [1]. The commensurability condition is described by an equation of integers [1]. At first glance, its distribution as a function of normalized electron density ν seems completely irregular. In this work, a twelvefold symmetry has been found, allowing for the identification of strong degeneracies. Analytical and numerical analysis revealed various unexpected properties such as that distances of commensurate ν−1 tend to be divisible by three or that the minimal distance of commensurate ν−1 always keeps appearing even for ν−1 going towards infinity.
[1] W. Häusler: Phys. Rev. B 91, 041102 (2015)
[2] B. Sutherland: Phys. Rev. B 34, 5208 (1986)