Regensburg 2016 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe
O: Fachverband Oberflächenphysik
O 16: Surface State Spectroscopy II
O 16.10: Vortrag
Montag, 7. März 2016, 17:15–17:30, H4
Electronic correlations in two-dimensional surface triangular lattices — •Florian Adler1, Gang Li2, Andrzej Fleszar2, Felix Reis1, Werner Hanke2, Jörg Schäfer1, and Ralph Claessen1 — 1Physikalisches Institut and Röntgen Center for Complex Material Systems (RCCM), Universität Würzburg, Germany — 2Institut für Theoretische Physik und Astrophysik, Universität Würzburg, Germany
We have examined the electronic structure of two related adatom systems, namely the √3 × √3 reconstructions of Sn on SiC(0001) and the γ-phase of Pb on Si(111). In either case, the adatoms form a congeneric two-dimensional triangular lattice on their respective substrate, leaving one dangling bond unsaturated. Despite the half-filled surface band, both systems end up in a Mott insulating state due to electronic correlations. In order to grasp the emerging physics, we have analyzed their spectral functions using angle-resolved photoemission spectroscopy.
Interestingly, one clearly observes a qualitatively different distribution of spectral weight within the lower Hubbard band of the two systems. Depending on the strength of local and non-local Coulomb interactions as well as spin interactions, each system responds differently to the frustration imposed by the triangular geometry of the substrate. This results in a possible charge or spin order, which sets its fingerprint on the symmetry and weight distribution of the k-resolved spectral function. The responsible order mechanism can then be tracked down with the help of many-body calculations. First studies on the spectral functions and a comparison between the two systems will be presented.