Dirac semimetal in type-IV magnetic space groups

Analogs of the elementary particles, Dirac fermions in condensed matter, have received extensive attention for both scientific interest and device applications. In this Rapid Communication, we study the Dirac semimetals (DSMs) in the magnetic space groups (MSGs), and find a category of DSMs in centrosymmetric type-IV MSGs, where the Dirac points (DPs) are protected by inversion symmetry, nonsymmorphic time-reversal symmetry, and suitable rotation symmetry. Moreover, we propose the interlayer antiferromagnetic (AFM) material EuCd2As2 as a promising candidate hosting only one pair of such DPs at the Fermi level. Many exotic topological states, such as the AFM triple-point semimetal, an AFM topological insulator exhibiting the half-quantum Hall effect, can be derived from such AFM DSMs by breaking certain symmetry. Our results extend the range of DSMs, and provide a platform to study the topological phase transition and the exotic properties of AFM topological states.