"Dirac fermions in an antiferromagnetic semimetal"

Peizhe Tang: Quan Zhou, Gang Xu & Shou-Cheng Zhang; NATURE PHYSICS, 08/08/16.

Additional Authors: Quan Zhou, Gang Xu & Shou-Cheng Zhang

Abstract:

Analogues of the elementary particles have been extensively searched for in condensed-matter systems for both scientific interest and technological applications123. Recently, massless Dirac fermions were found to emerge as low-energy excitations in materials now known as Dirac semimetals456. All of the currently known Dirac semimetals are non-magnetic with both time-reversal symmetry  and inversion symmetry    789. 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.