title: Butterfly magnetoresistance, quasi-2D Dirac Fermi surface and topological phase transition in ZrSiS.
abstract: Magnetoresistance (MR), the change of a material's electrical resistance in response to an applied magnetic field, is a technologically important property that has been the topic of intense study for more than a quarter century. We report the observation of an unusual "butterfly"-shaped titanic angular magnetoresistance (AMR) in the nonmagnetic Dirac material, ZrSiS, which we find to be the most conducting sulfide known, with a 2-K resistivity as low as 48(4) nΩ⋅cm. The MR in ZrSiS is large and positive, reaching nearly 1.8 × 105percent at 9 T and 2 K at a 45° angle between the applied current (I||a) and the applied field (90° isH||c). Approaching 90°, a "dip" is seen in the AMR, which, by analyzing Shubnikov de Haas oscillations at different angles, we find to coincide with a very sharp topological phase transition unlike any seen in other known Dirac/Weyl materials. We find that ZrSiS has a combination of two-dimensional (2D) and 3D Dirac pockets comprising its Fermi surface and that the combination of high-mobility carriers and multiple pockets in ZrSiS allows for large property changes to occur as a function of angle between applied fields. This makes it a promising platform to study the physics stemming from the coexistence of 2D and 3D Dirac electrons as well as opens the door to creating devices focused on switching between different parts of the Fermi surface and different topological states.
authors.affiliation: IBM Almaden Research Center, 650 Harry Road, San Jose, CA 95120, USA.; Max Planck Institute of Microstructure Physics, Weinberg 2, 06120 Halle, Germany.
authors.forename: Mazhar N
authors.identifier: 0000-0002-1129-6105
authors.initials: MN
authors.lastname: Ali
authors.affiliation: Max Planck Institute for Solid State Research, Heisenbergstasse 1, 70569 Stuttgart, Germany.
authors.forename: Leslie M
authors.identifier: 0000-0003-3459-4241
authors.initials: LM
authors.lastname: Schoop
authors.affiliation: IBM Almaden Research Center, 650 Harry Road, San Jose, CA 95120, USA.; Max Planck Institute of Microstructure Physics, Weinberg 2, 06120 Halle, Germany.
authors.forename: Chirag
authors.initials: C
authors.lastname: Garg
authors.affiliation: Max Planck Institute for Solid State Research, Heisenbergstasse 1, 70569 Stuttgart, Germany.
authors.forename: Judith M
authors.initials: JM
authors.lastname: Lippmann
authors.affiliation: IBM Almaden Research Center, 650 Harry Road, San Jose, CA 95120, USA.
authors.forename: Erik
authors.initials: E
authors.lastname: Lara
authors.affiliation: Max Planck Institute for Solid State Research, Heisenbergstasse 1, 70569 Stuttgart, Germany.; Department of Chemistry, Ludwig-Maximilians-Universität München, Butenandtstrasse 5-13, 81377 München, Germany.
authors.forename: Bettina
authors.initials: B
authors.lastname: Lotsch
authors.affiliation: IBM Almaden Research Center, 650 Harry Road, San Jose, CA 95120, USA.; Max Planck Institute of Microstructure Physics, Weinberg 2, 06120 Halle, Germany.
authors.forename: Stuart S P
authors.initials: SS
authors.lastname: Parkin
keywords: Dirac; Line node; Magneto-resistance; Phase transition; Semimetal; Sulfide; Topological; Weyl; ZrSiS; topological insulator