Narrow-band tunable terahertz detector in antiferromagnets via staggered-field and antidamping torques

摘要

We study dynamics of antiferromagnets induced by simultaneous application of dc spin current and ac charge current, motivated by the requirement of all-electrically controlled devices in the terahertz (THz) gap (0.1-30 THz). We show that ac electric current, via Neel spin-orbit torques, can lock the phase of a steady rotating Neel vector whose precession is controlled by a dc spin current. In the phase-locking regime the frequency of the incoming ac signal coincides with the frequency of auto-oscillations, which for typical antiferromagnets falls into the THz range. The frequency of auto-oscillations is proportional to the precession-induced tilting of the magnetic sublattices related to the so-called dynamical magnetization. We show how the incoming ac signal can be detected and formulate the conditions of phase locking. We also show that the rotating Neel vector can generate ac electrical current via inverse Neel spin-orbit torque. Hence, antiferromagnets driven by dc spin current can be used as tunable detectors and emitters of narrow-band signals operating in the THz range.