Two-dimensional type-II Dirac fermions in a LaAlO3/LaNiO3/LaAlO3 quantum well

ORAL

Abstract

The type-II Dirac fermions that are characterized by a tilted Dirac cone and anisotropic magnetotransport properties have been recently proposed theoretically and confirmed experimentally. Here, we predict the emergence of two-dimensional (2D) type-II Dirac fermions in LaAlO3/LaNiO3/LaAlO3 quantum-well structures. Using first-principles calculations and model analyses, we show that the Dirac points are formed at the crossing between the dx2−y2 and dz2 bands protected by the mirror symmetry. The energy position of the Dirac points can be tuned to appear at the Fermi energy by changing the quantum-well width. For the quantum-well structure with a two-unit-cell-thick LaNiO3 layer, we predict the coexistence of the type-II Dirac point and the closed nodal line. The results are analyzed and interpreted using a tight-binding model and symmetry arguments. Our findings offer a practical way to realize 2D type-II Dirac fermions in oxide heterostructures.

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Presenters

  • Lingling Tao

    Department of Physics and Astronomy & Nebraska Center for Materials and Nanoscience, University of Nebraska-Lincoln, Institute of Physics, University of Nebraska - Lincoln

Authors

  • Lingling Tao

    Department of Physics and Astronomy & Nebraska Center for Materials and Nanoscience, University of Nebraska-Lincoln, Institute of Physics, University of Nebraska - Lincoln

  • Evgeny Y Tsymbal

    Department of Physics and Astronomy & Nebraska Center for Materials and Nanoscience, University of Nebraska, Lincoln, University of Nebraska - Lincoln, Department of Physics and Astronomy & Nebraska Center for Materials and Nanoscience, University of Nebraska-Lincoln, Department of Physics and Astronomy & Nebraska Center for Materials and Nanoscience, University of Nebraska - Lincoln, Institute of Physics