Berlin 2018 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 80: Graphene
TT 80.9: Vortrag
Donnerstag, 15. März 2018, 11:45–12:00, H 3005
Extreme magneto resistance in Ar+ ion radiated graphene — •Paul Linsmaier1, Lorenz Weiss1, Tobias Weinberger1, Ferdinand Kißlinger2, Heiko B. Weber2, and Christoph Strunk1 — 1Inst. f. Exp. and Appl. Physics, University of Regensburg — 2Fac. of Physics, F.-A. University Erlangen-Nürnberg
We report on magnetotransport measurements of epitaxial graphene on SIC [1], bombarded with Ar+ ions. For different strength of disorder, ρ(300K)=15−30kΩ, an Arrhenius temperature dependence of the resistance is found at low temperatures and zero magnetic field. In perpendicular magnetic field, we see a drastic change in the conductivity from Arrhenius (B=0T) to Efros-Shklovskii (B⊥=12T) Coulomb-gap-like behavior, with an extreme negative magnetoresistance (NMR) of ρ(B⊥)/ρ(0)<0.01 at B=12T and 300mK. This might indicate a gap, resulting from magnetic interactions in graphene.
In parallel magnetic field, we find a much smaller magnetoresistance with a sign change from a NMR at low temperatures to a positive magnetoresistance with increasing temperature and magnetic field.
K. V. Emtsev et al., Nat. Mat. 8, 203 - 207 (2009).