A New Three-Dimensional Subsulfide Ir2In8S with Dirac Semimetal Behavior

Dirac and Weyl semimetals host exotic quasiparticles with unconventional transport properties, such as high magnetoresistance and carrier mobility. Recent years have witnessed a huge number of newly predicted topological semimetals from existing databases; however, experimental verification often lags behind such predictions. Common reasons are synthetic difficulties or the stability of predicted phases. Here, we report the synthesis of the type-II Dirac semimetal IrInS, an air-stable compound with a new structure type. This material has two Dirac crossings in its electronic structure along the &-Z direction of the Brillouin zone. We further show that IrInS has a high electron carrier mobility of ∼10 »000 cm/(V s) at 1.8 K and a large, nonsaturating transverse magnetoresistance of ∼6000% at 3.34 K in a 14 T applied field. Shubnikov de-Haas oscillations reveal several small Fermi pockets and the possibility of a nontrivial Berry phase. With its facile crystal growth, novel structure type, and striking electronic structure, IrInS introduces a new material system to study topological semimetals and enable advances in the field of topological materials.This work was supported by the National Science Foundation (NSF) grant DMR-1708254 (synthesis and structural characterization). Transport and magnetic property measurements were performed at Argonne National Laboratory supported by the U.S. Department of Energy (DOE), Office of Science, Basic Energy Sciences (BES), Materials Sciences and Engineering Division. Single-crystal diffraction data were performed at the IMSERC facility at Northwestern University, which has received support from the Soft and Hybrid Nanotechnology Experimental (SHyNE) Resource (NSF NNCI-1542205); the State of Illinois; and International Institute for Nanotechnology (IIN). The work for preliminary DFT calculations and partial density of states calculations carried out by J.E.P. and C.W. was supported by the U.S. Department of Energy, Office of Science Basic Energy Sciences grant DE-SC0014520. L.M.S. was supported by NSF through the Princeton Center for Complex Materials, a Materials Research Science and Engineering Center DMR-1420541, and by a MURI grant on Topological Insulators from the Army Research Office, grant number ARO W911NF-12-1-0461. M.G.V. and A.B. acknowledge the IS2016-75862-P and FIS2016-76617-P national projects of the Spanish MINECO and the Department of Education, Universities and Research of the Basque Government and the University of the Basque Country (IT756-13)