A controlled rotation of magnetic moments' orientation by means of an applied electrical field has been demonstrated in tetragonal CuMnAs [1]. This effect originates from spin-orbit torque and allows for a creation of a unique non-volatile memory device faster than flash memory and robust against magnetic field. Furthermore, it can be used to construct micron-size bit cells acting as a multi-level memory-counter [2] with potential applications in nanoelectronics. However, bulk CuMnAs natively crystallizes in the orthorhombic phase, which has different interesting properties. Tetragonal CuMnAs phase has been achieved in epitaxially deposited samples or by inserting lattice defects linked to non-stoichiometry in CuMnAs [3].

Electronic, magnetic, and transport properties of the antiferromagnetic (AFM) CuMnAs alloy with both tetragonal and orthorombic structure are studied here from first principles using the total energy calculations [4]. We have estimated the stability of different phases and calculate formation energies of possible defects in the alloy [3]. Antisites and vacancies on Mn or Cu sublattices were identified as most probable defects in CuMnAs. We have found that the interactions of the growing thin film with the substrate and with vacuum are important for the phase stability of real samples prepared as a thin film on the appropriate substrate. We estimated also the in-plane resistivity of CuMnAs with defects of low formation energies. Our numerical simulations fitted experiment very well if we assumed concentrations of 3.5-5% antisites [4]. Finally, we have determined the exchange interactions and estimate the Néel temperature of the ideal and disordered AFM-CuMnAs alloy using the Monte Carlo approach. The decrease of the Néel temperature in the presence of antisites and vacancies has been evaluated as well [5]. A good agreement of the calculated resistivity and Néel temperature with experimental data makes it possible to estimate the structure and composition of real CuMnAs samples.