Berlin 2018 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 80: Graphene

TT 80.1: Vortrag

Donnerstag, 15. März 2018, 09:30–09:45, H 3005

Transport in systems with nodal degeneracy — •Andreas Sinner and Klaus Ziegler — Institut für Physik, Theorie II Universität Augsburg Universitätsstr. 1 D-86159, Augsburg, Germany

We study the DC conductivity of a weakly disordered 2D electron gas with two bands and spectral nodes, employing the field theoretical version of the Kubo-Greenwood conductivity formula. Disorder scattering is treated within the standard perturbation theory by summing up ladder and maximally crossed diagrams. The emergent gapless (diffusion) modes determine the behavior of the conductivity on large scales. We find a finite conductivity with an intermediate logarithmic finite-size scaling towards smaller conductivities but do not obtain the logarithmic divergence of the weak-localization approach. Our results agree with the experimentally observed logarithmic scaling of the conductivity in graphene with the formation of a plateau near the universal conductivity. We extend our analysis by including effects of anisotropy on hexagonal lattices.
A. Sinner, K. Ziegler, Phys. Rev. B 90, 174207 (2014).
A. Sinner, K. Ziegler, J. Phys. Condens. Matter. 28, 305701 (2016).
A. Sinner, K. Ziegler, Europhys. Lett. 119, 27001 (2017).