Regensburg 2019 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 48: Topological Semimetals - Experiment (joint session TT/MA)
MA 48.6: Vortrag
Donnerstag, 4. April 2019, 16:15–16:30, H2
ZrP2 family of materials as topological semimetal candidates — Jörn Bannies1,2, Elia Razzoli2, Matteo Michiardi1,2, •Ilya Elfimov2, Andrea Damascelli2, and Claudia Felser1 — 1Max Planck Instistute for Chemical Physics of Solids, Dresden, Germany — 2Quantum Matter Institute, University of British Columbia, Vancouver, Canada
In recent years transition metal pnictides including dipnictides have attracted much research interest in the context of topological semimetals. These include type-I and type-II Weyl semimetals, triple-point fermions and weak topological insulators. Here we propose group IV dipnictides as potential nodal line semimetals, a class with only a few verified members to date.
We have successfully grown crystals of ZrP2 and ZrAs2 and, for the first time, investigated their transport properties. These materials are isostructural and crystallize in the non-symmorphic space group Pnma. For ZrP2 an unsaturated magnetoresistance of 1.5·104 % at 2 K and 9 T with nearly quadratic field dependence is observed. This is accompanied by a resistivity plateau up to 20 K in high magnetic fields. Similar behavior in other topological semimetals suggests a topological origin. Indeed, ZrX2 (X = P, As) compounds were recently identified as topological materials. Our DFT band structure calculations show a Dirac like band crossing close to the Fermi level as well as a nodal line in the kx=0 plane. We discuss the role of non-symmorphic symmetry in stabilizing these features.