Dirac fermions in an antiferromagnetic semimetal

By Peizhe Tang, Quan Zhou, Gang Xu, Shoucheng Zhang. Nature Physics, 2016

258 citations recorded by the source corpus.

The prediction of an antiferromagnetic semimetal that breaks both time-reversal and inversion symmetry but respects their combination could provide a platform for studying the interplay between Dirac fermions and magnetism. Analogues of the elementary particles have been extensively searched for in condensed-matter systems for both scientific interest and technological applications1,2,3. Recently, massless Dirac fermions were found to emerge as low-energy excitations in materials now known as Dirac semimetals4,5,6. All of the currently known Dirac semimetals are non-magnetic with both time-reversal symmetry and inversion symmetry 7,8,9. Here we show that Dirac fermions can exist in one type of antiferromagnetic system, where both and are broken but their combination is respected. We propose orthorhombic antiferromagnet CuMnAs as a candidate, analyse the robustness of the Dirac points under symmetry protections and demonstrate its distinctive bulk dispersions, as well as the corresponding surface states, by ab initio calculations. Our results provide a possible platform to study the interplay of Dirac fermion physics and magnetism.

Subfields: Atomic and Molecular Physics, and Optics, Condensed Matter Physics, Electronic, Optical and Magnetic Materials

View Paper: https://www.semanticscholar.org/paper/ec174d88323f9d39c6eff3735c594444220fa8b1

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In Atomic and Molecular Physics, and Optics

In Condensed Matter Physics

In Electronic, Optical and Magnetic Materials

Citations in the corpus

Chiral Anomaly from Strain-Induced Gauge Fields in Dirac and Weyl Semimetals (2016, result): “We emphasize that although the 1 2 -Cd3As2 model taken on its own does not describe any specific real material, the results we report for this model are relevant to a broad class of Weyl semimetals with broken T such as the Burkov-Balents layered heterostructure [26] and more recently proposed magne”
Intrinsic magnetic topological insulators in van der Waals layered MnBi2Te4-family materials (2018, background): “For AFM MnBi2Te4 films, even layers do not possess P and Q symmetries but have P2Q, ensuring double degeneracy in every band (22).”
Topological Semimetals from First Principles (2018, background): “Firstprinciples calculations predicted magnetic CuMnAs as a antiferromagnetic Dirac semimetal (73).”
Current-induced spin-orbit torques in ferromagnetic and antiferromagnetic systems (2018, background): “In the AF phase, this degeneracy is not lifted because the combined PT symmetry is preserved, although the T symmetry and the P symmetry are individually broken (Chen et al., 2014; Herring, 1966; Šmejkal et al., 2017; Tang et al., 2016).”
Antiferromagnetic spintronics (2016, background): “CuMnAs and Mn2Au crystals possess local inversion symmetry breaking in bulk crystal, as explained (see also Table III), and display anisotropic magnetoresistance allowing for the electrical detection of the order parameter orientation.”