Regensburg 2016 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 44: Transport: Graphene
(Joint session of DS, DY, HL, MA, O and TT organized by TT)

TT 44.9: Vortrag

Mittwoch, 9. März 2016, 12:00–12:15, H22

Linear magnetoresistance in two-dimensional disordered conductors — •Ferdinand Kisslinger¹, Christian Ott¹, Erik Kampert², and Heiko B. Weber¹ — ¹Lehrstuhl für Angewandte Physik, FAU Erlangen-Nürnberg (FAU), Erlangen, Germany. — ²Dresden High Magnetic Field Laboratory, Helmholtz-Zentrum Dresden-Rossendorf, Dresden, Germany.

The recent observation of linear magnetoresistance (MR) in large-area bilayer graphene gives a key to the understanding of this old and barely understood phenomenon [1]. In bilayer graphene, it can be traced back to mosaic-like pattern of a partial dislocation network [2]. In this talk we discuss how linear MR evolves in disordered samples, using a two dimensional resistor network model conceptually introduced by Parish and Littlewood [3]. This model is in the weak disorder regime dominated by boundary effects. We identified a new regime representing the bulk situation in a disordered conductor. We investigated different possible sources of disorder: mobility, charge carrier density and network structure. The slope of the MR turned out to be simply governed by the Hall resistance and therefore by the inverse of the charge carrier density. An equivalent circuit model finally gives a consistent explanation as to why the magnetoresistance is linear in mosaic like samples.

[1] F. Kisslinger et al., Nature Physics 11, 650 (2015)

[2] B. Butz et al., Nature 505, 533 (2014).

[3] M. M. Parish & P. B. Littlewood, Nature 426, 162 (2003)