Electronic structure calculations of intrinsic magnetic properties in antiferromagnetic CuMnAs

A lot of attention has been recently directed towards storing and manipulating information in the order parameter of an antiferromagnetic metal. An antiferromagnet creates no stray fields and is stable against demagnetization. Antiferromagnets with broken space inversion symmetry like tetragonal CuMnAs are of interest because their order parameter can be manipulated by current-induced torques [1,2,3]. The magnetocrystalline anisotropy (MCA) of CuMnAs is easy-plane [1], which is unfavorable for storing information. Here we predict, using first-principles calculations in the coherent potential approximation, that CuMnAs experiences a spin-reorientation transition under a small hole doping, which can be achieved by substituting 2-3% of Ge, Si, B, or Al for As. The maximum easy-axis MCA is reached at 10-15% substitution, while the exchange coupling is insensitive to this substitution. Calculations using the disordered local moment method reveal a monotonic temperature dependence of MCA with no anomalies.

[1] P. Wadley et al., Nature Comm. 4, 2322 (2013)
[2] P. Wadley et al., Science 351, 587(2016)
[3] T. Jungwirth et al., Nature Nanotechnology 11, 231(2016)