Calendar of Physics Talks Vienna

Intercalation in epitaxial graphene on SiC: From quasi-free standing graphene to superlattices
Speaker:Dr. Ulrich Starke (Max-Planck-Institut für Festkörperforschung, Stuttgart/Germany )
Abstract: Epitaxial graphene on SiC(0001) promises a scalable graphene technology. Different methods for homogeneous graphene growth and experimental techniques for layer counting will be reviewed. The graphene layers are n-doped due to the influence of a covalently bonded carbon interface layer. This influence can be completely eliminated by atomic intercalation. Hydrogen for example migrates under the interface layer, passivates the underlying SiC layer and decouples the graphene from the substrate. The interface layer alone transforms into a quasi-free standing monolayer while monolayers and bilayers turn into decoupled bilayers and trilayers. As a result, charge neutral quasi free graphene layers can be obtained. By intercalation of Germanium the graphene layers can also be decoupled. In this process both p- and n-doping can be produced, depending on the amount of Ge material intercalated. Both phases can be prepared in coexistence on the surface. In this way, lateral p-n junctions can be obtained on a sub-micron scale. Intercalation of Cu induces a coincidence superstructure on top of the SiC surface, which originates from periodic regions of different bond configuration for the carbon atoms in the graphene layer. As a result, a long range periodic potential is imposed onto the graphene layer, which leads to a profound modification of its electronic spectrum. A surprisingly strong doping and the development of mini-Dirac cones are observed.
Date: Tue, 26.06.2012
Time: 16:00
Location:Technische Universität Wien, Institut für Angewandte Physik, Seminarraum 134A, Turm B (gelbe Leitfarbe), 5. OG, 1040 Wien, Wiedner Hauptstraße 8-10
Contact:Ao.Univ.Prof. Dr. Josef Redinger

Constraining CP violation in neutral meson mixing with theory input
Speaker:Sacha Turczyk (LBL, Berkely)
Abstract:im Rahmen des Teilchenphysikseminars
Date: Thu, 28.06.2012
Time: 14:15
Duration: 60 min
Location:Fakultät für Physik, Erwin Schrödinger-Hörsaal, Boltzmanngasse 5, 5. Stock
Contact:A. Hoang

Smoothness of closed relativistic strings in 2+1 vacuum spacetimes
Speaker:Luc Nguyen (Princeton)
Abstract:im Rahmen des Literaturseminars
Date: Thu, 28.06.2012
Time: 14:15
Duration: 60 min
Location:Arbeitsgruppe: Gravitation, Währinger Strasse 17, Seminarraum A, 2. Stock
Contact:R. Beig