Although magnetoelectric effects in metals are usually neglected, assuming that applied electric fields are screened by free charge carriers, the skin depth, defining the penetration depth of the fields, is nonzero and for terahertz electric fields typically reaches 400 nm. Hence, if the thickness of an antiferromagnetic film is of the order of tens of nanometers, electric field induced effects cannot be neglected. Here, we theoretically study the terahertz electric field induced spin dynamics in the metallic antiferromagnet ${\mathrm{Mn}}_2\mathrm{Au}$, the spin arrangements of which allow it to exhibit a linear magnetoelectric effect. We show that the terahertz magnetoelectric torque in metallic antiferromagnets is proportional to the time derivative of the polarization induced by the terahertz electric field. Our simulations reveal that the magnetoelectric driven spin dynamics is indeed not negligible, and for a fair explanation of previously published experimental results in ${\mathrm{Mn}}_2\mathrm{Au}$ competition between terahertz magnetoelectric and Néel spin-orbit torques must be taken into account. Thus, it is shown that even in metallic antiferromagnets the terahertz magnetoelectric effect on spins can be strong and thus cannot be neglected.

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• Magnetoelectric effect
• Spin dynamics
• Ultrafast magnetic effects
• Antiferromagnets