Berlin 2018 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 80: Graphene

TT 80.12: Talk

Thursday, March 15, 2018, 12:30–12:45, H 3005

Logarithmic Low-Bias Anomalies in the Differential Conductance of Graphene Structures — •Matthias Popp, Ferdinand Kißlinger, and Heiko B. Weber — Friedrich-Alexander-Universität Erlangen-Nürnberg Lehrstuhl für Angewandte Physik Staudtstraße 7 91058 Erlangen

We measured the voltage-dependent differential conductance of graphene-graphene tunneling junctions at low temperatures in order to probe electron-electron interaction corrections on the density of states (DOS). As predicted by Altshuler and Aronov [1] a logarithmic voltage dependence was observed [2]. Tunneling junctions provide a sharp voltage drop, therefore their differential conductance is a good measure for the DOS. To our surprise we also found logarithmic voltage dependencies in the differential conductance of graphene stripes where no sharp voltage drop is present. We explain this with a model involving voltage dependent heating of electrons in combination with electron-electron interaction as well as weak localization corrections to conductivity, both of which exhibit a logarithmic temperature dependence. We give an overview how to differentiate between these effects which all manifest themselves in logarithmic low-bias anomalies in differential conductance.
B. Altshuler, A. Aronov, Electron-Electron Interactions in Disordered Systems, North Holland (1985)
F. Kisslinger, et al., Annalen der Physik 1700048 (2017)