Regensburg 2019 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 56: Topological Semimetals - Experiment (joint session TT/MA)
TT 56.2: Vortrag
Donnerstag, 4. April 2019, 15:15–15:30, H2
Absence of the chiral anomaly - the longitudinal magnetoresistance in TaAs-type Weyl metals — •Marcel Naumann1,2, Frank Arnold1, Maja Bachmann1, Kimberley Modic1, Vicky Süß1, Marcus Schmidt1, Philip Moll1, Brad Ramshaw3, and Elena Hassinger1,2 — 1MPI CPfS, Dresden, Germany — 2Technische Universität München, Garching, Germany — 3Cornell University, Ithaca, NY, USA
The discovery of materials with 3D linear band-crossing points close to the Fermi level, such as Dirac and Weyl semimetals, has offered the possibility to study relativistic fermions in solid state systems. One manifestation, the ’chiral anomaly’, should appear as a reduction of the longitudinal magnetoresistance (LMR), as was quickly observed in TaAs [1]. Subsequent studies found that current inhomogeneities (’current jetting’) often induce an apparent negative LMR in semimetals, and that the true LMR is still unknown [2,3].
In this study, we determine the intrinsic LMR in the TaAs family (TaAs, TaP, NbAs, NbP) of Weyl semimetals. We reduced current jetting effects by trying to achieve a homogeneous current injection and by increasing the aspect ratio of our samples. The results show an absence of the negative LMR in chiral materials and a presence of a negative LMR in non-chiral materials. This suggests a chirality independent effect, which we believe to be weak-localisation physics.
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