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Gaku Eguchi, S. Paschen:
"Precise analysis of two-carrier transport";
Poster: Research Workshop On Spin, Charge, And Energy Currents In Novel Materials, Hvar, Croatia; 01.10.2017 - 07.10.2017.

The recent excitement about Dirac and Weyl fermion systems has renewed interest in magnetotransport properties of multi-carrier systems. However, the complexity of their analysis, even in the simplest two-carrier case, has hampered a good understanding of the underlying phenomena. In fact, difficulties in analysing magnetotransport properties of even simple (non-topological) two-band systems were already recognized in the 1970s, and unreliable results were attributed to the large number of open parameters [1].
Recently, we have established a new analysis scheme for two independent conduction channels that strongly reduces the numerical uncertainty, and therefore allows to draw ro- bust conclusions [2]. By employing numerical analyses it also clarifies the exact physical meaning of the charge neutrality and of the non-saturating huge linear transverse magne- toresistance.
In this presentation we explain details and demonstrate magnetotransport behaviour of three-dimensional topological insulators as an example. From the new scheme, we can also extract the upper limit of the transverse magnetoresistance. Remarkably, none of the topologically non-trivial insulators or semimetals, even in the recently highlighted Dirac or Weyl semimetals, violates this limit. We discuss the physical implications in the context of actual experiments.