Semi-Dirac and Weyl Fermions in Transition Metal Oxides

Abstract

We show that a class of compounds with $I$4/$mcm$ crystalline symmetry hosts three-dimensional semi-Dirac fermions. Unlike the known two-dimensional semi-Dirac points, the degeneracy of these three-dimensional semi-Dirac points is not lifted by spin-orbit coupling due to the protection by a nonsymmorphic symmetry -- screw rotation in the $a-b$ plane and a translation along the $c$ axis. This crystalline symmetry is found in tetragonal perovskite oxides, realizable in thin films by epitaxial strain that results in a${}^0$a${}^0$c${}^{-}$-type octahedral rotation. Interestingly, with broken time-reversal symmetry, two pairs of Weyl points emerge from the semi-Dirac points within the Brillouin zone, and an additional lattice distortion leads to enhanced intrinsic anomalous Hall effect. The ability to tune the Berry phase by epitaxial strain can be useful in novel oxide-based electronic devices.

References in corpus (20)

• The electronic properties of graphene
• The electronic properties of bilayer graphene
• Time Reversal Polarization and a Z_2 Adiabatic Spin Pump
• Classification of stable three-dimensional Dirac semimetals with nontrivial topology
• Topological Semimetals
• Computing topological invariants without inversion symmetry
• A new magnetic field dependence of Landau levels on a graphene like structure
• Nonsymmorphic-symmetry-protected hourglass Dirac loop, nodal line, and Dirac point in bulk and monolayer $X_3$SiTe${}_6$ ($X=$ Ta, Nb)
• Substrate coherency-driven octahedral rotations in perovskite oxide films
• A semi-Dirac point in the Hofstadter spectrum
• Nonlinear magnetotransport shaped by Fermi surface topology and convexity in WTe2
• Floquet band structure of a semi-Dirac system
• Floquet dynamics in two-dimensional semi-Dirac semimetals and three-dimensional Dirac semimetals
• Exhaustive constructions of effective models in 1651 magnetic space groups
• Interplay between topology and disorder in a two-dimensional semi-Dirac material
• Symmetry-enforced band crossings in tetragonal materials: Dirac and Weyl degeneracies on points, lines, and planes
• Fermi surface topology and large magnetoresistance in the topological semimetal candidate PrBi
• Interplay of Coulomb interaction and disorder in a two-dimensional semi-Dirac fermion system
• Accidental Degeneracy in k-space, Geometrical Phase, and the Perturbation of $\pi$ by Spin-orbit Interactions
• Power law decay of local density of states oscillations near a line defect in a system with semi-Dirac points

Cited by in corpus (1)

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