Abstract
Recently, orthorhombic CuMnAs has been proposed to be a magnetic material where topological fermions exist around the Fermi level. Here we report the magnetic structure of the orthorhombic Cu0.95MnAs and Cu0.98Mn0.96As single crystals. While Cu0.95MnAs is a commensurate antiferromagnet below 360 K with a propagation vector of k=0,Cu0.98Mn0.96As undergoes a second-order paramagnetic to incommensurate antiferromagnetic phase transition at 320 K with k=(0.1,0,0), followed by a second-order incommensurate to commensurate antiferromagnetic phase transition at 230 K. In the commensurate antiferromagnetic state, the Mn spins order parallel to the crystallographic b axis but antiparallel to their nearest neighbors, with the spin orientation along the b axis. This magnetic order breaks S2z, the two-fold rotational symmetry around the c axis, resulting in finite band gaps at the crossing point and the disappearance of the massless topological fermions. However, our first-principles calculations suggest that orthorhombic CuMnAs can still host spin-polarized surface states and signature induced by nontrivial topology, which makes it a promising candidate for antiferromagnetic spintronics.
| Original language | English |
|---|---|
| Article number | 224405 |
| Journal | Physical Review B |
| Volume | 96 |
| Issue number | 22 |
| DOIs | |
| State | Published - Dec 4 2017 |
Funding
Work at UCLA was supported by the U.S. Department of Energy (DOE), Office of Science, Office of Basic Energy Sciences under Award No. DE-SC0011978. Work at High Flux Isotope Reactor was sponsored by the Scientific User Facilities Division, Office of Basic Energy Sciences, DOE. The research at LSU was supported by the LSU-startup funding and Louisiana Board of Regents Research Competitiveness Subprogram under Contract No. LEQSF (2017-20)-RD-A-08. P.Z. and S.C.Z. acknowledge FAME, one of six centers of STARnet, a Semiconductor Research Corporation program sponsored by MARCO and DARPA. N.N. thanks Dr. Y. Wang for useful discussion.