Highly anisotropic Dirac fermions in a Bi square net of SrMnBi$_2$

ORAL

Abstract

We report the highly anisotropic Dirac fermions in a Bi square net of SrMnBi$_2$, based on a first principle calculation, angle resolved photoemission spectroscopy, and quantum oscillations for high-quality single crystals. We found that the Dirac dispersion is generally induced in the (SrBi)$^{+}$ layer containing a double-sized Bi square net. In contrast to the commonly observed isotropic Dirac cone, the Dirac cone in SrMnBi$_2$ is highly anisotropic with a large momentum-dependent disparity of Fermi velocities of $\sim 8$. These findings demonstrate that a Bi square net, a common building block of various layered pnictides, provide a new platform that hosts highly anisotropic Dirac fermions.

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Authors

  • Jun Sung Kim

    • POSTECH
    • Department of Physics, Pohang University of Science and Technology

  • Joonbum Park

    • Department of Physics, Pohang University of Science and Technology

  • Geunsik Lee

    • Department of Chemistry, Pohang University of Science and Technology

  • Frederik Wolff-Fabris

    • Dresden High Magnetic Field Laboratory, Helmholtz-Zentrum Dresden-Rossendorf

  • Yoon Young Koh

    • Institute of Physics and Applied Physics, Yonsei University

  • Man Jin Eom

    • Department of Physics, Pohang University of Science and Technology

  • Yeongkwan Kim

    • Institute of Physics and Applied Physics, Yonsei University

  • M.A. Farhan

    • Department of Chemistry, Pohang University of Science and Technology

  • Younjung Jo

    • Department of Physics, Kyungpook National University

  • Changyoung Kim

    • Institute of Physics and Applied Physics, Yonsei University, Seoul 120-749, Korea

  • Ji Hoon Shim

    • Department of Chemistry, Pohang University of Science and Technology, Pohang 790-784, Korea