Observation of Dirac nodal lines in rutile oxide IrO2

ORAL

Abstract

The complex oxide IrO2 is predicted to be a dirac nodal line semimetal protected by nonsymmorphic symmetry. Some of its intriguing physical properties include a large spin hall effect, significant magnetoresistance, and a hall effect where the sign of the carrier may be controlled by an external magnetic field. Previously there has been no direct evidence of the topological features of the band structure. This is a non trivial prediction because the relevant orbitals Ir 5d and O 2p are known to often host strong electron correlations and spin orbit coupling. Using a combination of reactive oxide molecular beam epitaxy and Angle-Resolved Photoemission Spectroscopy we show that IrO2 is a Dirac nodal line semimetal in agreement with the predictions of Sun et. al. This is the first experimental observation of nodal lines protected by nonsymmorphic symmetry. Significantly the crossing points are protected even in the case of large spin orbit coupling characteristic of iridates. Furthermore they cross the fermi level making IrO2 an ideal system to study the low energy properties of Dirac nodal line materials.

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Presenters

  • Jocienne Nelson

    Cornell University

Authors

  • Jocienne Nelson

    Cornell University

  • Luca Moreschini

    Cornell University

  • Jason Kawasaki

    Univ of Wisconsin, Madison, Cornell University, Wisconsin-Madison, University of Wisconsin, Madison

  • Eli Rotenberg

    Advanced Light Source, E.O. Lawrence Berkeley National Lab, Berkeley, CA 94720, USA, Advanced Light Source, Lawrence Berkeley National Laboratory, ALS, Lawrence National Berkeley Laboratory, Advanced Light Source, Lawrence Berkeley National Lab, Lawrence Berkeley National Laboratory, Advanced Light Source (ALS), E. O. Lawrence Berkeley National Laboratory, USA, Advanced Light Source, E. O. Lawrence Berkeley National Laboratory

  • Darrell G. Schlom

    Cornell University, Cornell University, Ithaca, New York 14853, USA, Department of Materials Science and Engineering, Cornell University, Department of Materials Science and Engineering, Kavli Institute at Cornell for Nanoscale Science, Cornell University, Materials Science & Engineering, Cornell University, Department of Materials Science and Engineering,, Cornell University, Materials Science and Engineering, University of Cornell

  • Kyle M Shen

    Cornell University, Department of Physics, Laboratory of Atomic and Solid State Physics, Kavli Institute at Cornell for Nanoscale Science, Cornell University