Picosecond Electric-Field-Induced Switching of Antiferromagnets

We propose a method for switching the Neel vector of an antiferromagnetic thin film by the application of an ultrashort electric field pulse. The electric field induces a reorientation of the antiferromagnetic order parameter due to the voltage-induced modification of the magnetic anisotropy. When the electric field pulse is timed to half the oscillation period of the terahertz antiferromagnetic dynamics, it induces a picosecond-timescale reversal of the Neel vector. Importantly, the electric field required to induce this reversal is as small as approximately 100 mV/nm, comparable to fields used for switching of ferromagnetic tunnel junctions in earlier works. This electric field is determined by the anisotropy of the antiferromagnet, while the much larger exchange field determines the frequency of the resulting dynamics (and hence the switching time). Our results indicate the possibility to switch a 50-nm circular antiferromagnetic element with an energy dissipation of 250 aJ in less than 30 ps and in the absence of any current-induced torque. The electric-field-induced switching of the Neel vector opens an alternative route toward energy-efficient and ultrafast magnetic memories and computing devices based on antiferromagnets.