Evolution of Weyl fermions along the polarity reversal paths in MoTe2

ORAL

Abstract

MoTe2 is a layered material with rich physics arising from structural and electronic phase competition. The three observed crystal phases - 2H, 1T′, and Td - have distinct electronic properties. The non-centrosymmetric Td -MoTe2 is particularly fascinating due to the presence of type-I and type-II Weyl nodes in this system. In this study, we investigate the energetics of the possible structural phase transitions in MoTe2, and explore the possibility of controlling the dynamics of Weyl fermions in MoTe2. Our first-principles calculations reveal that one can systematically tune the location and chirality of Weyl nodes by exploiting the connection between polar distortions and spin-orbit coupling effects in Td - MoTe2. By restoring the broken inversion symmetry, we locate a highly symmetric saddle point structure (Td0) on the energy landscape of MoTe2, establishing a polarity reversal path connecting up and down variants of Td. The Td0 phase resembles a paraelectric phase of a ferroelectric compound, and it is dynamically and elastically unstable leading to structural phase transitions into the Td and 1T′ phases. We study the evolution of Weyl nodes as a function of structural distortions in the vicinity of Td0.

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Presenters

  • Sobhit Singh

    Department of Physics and Astronomy, Rutgers University, Piscataway, NJ-08854, USA

Authors

  • Sobhit Singh

    Department of Physics and Astronomy, Rutgers University, Piscataway, NJ-08854, USA

  • Jinwoong Kim

    Rutgers University, New Brunswick, Department of Physics and Astronomy, Rutgers University, Piscataway, NJ-08854, USA, Physics and Astronomy, Rutgers University, New Brunswick, Department of Physics and Astronomy, Rutgers University, New Jersey

  • Karin Rabe

    Rutgers University, New Brunswick, Department of Physics and Astronomy, Rutgers University, Piscataway, NJ-08854, USA, Physics and Astronomy, Rutgers University, Piscataway, NJ, United States

  • David Vanderbilt

    Rutgers University, New Brunswick, Department of Physics and Astronomy, Rutgers University, Department of Physics and Astronomy, Rutgers University, Piscataway, NJ-08854, USA, Physics and Astronomy, Rutgers University, New Brunswick, Department of Physics and Astronomy, Rutgers University, New Jersey, Rutgers University, USA, Rutgers Univ, Physics and Astronomy, Rutgers University, Piscataway, NJ, United States, Department of Physics and Astronomy, Rutgers University, Piscataway, NJ, USA