Voltage-Controlled High-Bandwidth Terahertz Oscillators Based On Antiferromagnets

TL;DR

This paper demonstrates that noncollinear antiferromagnets with kagome structure can generate tunable, high-frequency terahertz oscillations controlled by voltage via spin-orbit torques, offering new potential for THz technology.

Contribution

It introduces a theoretical framework showing how NCAFMs can produce voltage-controlled, tunable THz oscillations based on their chirality-dependent dynamics.

Findings

NCAFMs host gapless self-oscillations tunable from 0 Hz to THz.

The dynamics depend on the ground state's chirality.

NCAFMs can serve as functional components in THz technology.

Abstract

Producing compact voltage-controlled frequency generators and sensors operating in the terahertz (THz) regime represents a major technological challenge. Here, we show that noncollinear antiferromagnets (NCAFM) with kagome structure host gapless self-oscillations whose frequencies are tunable from 0 Hz to the THz regime via electrically induced spin-orbit torques (SOTs). The auto-oscillations' initiation, bandwidth, and amplitude are investigated by deriving an effective theory, which captures the reactive and dissipative SOTs. We find that the dynamics strongly depends on the ground state's chirality, with one chirality having gapped excitations, whereas the opposite chirality provides gapless self-oscillations. Our results reveal that NCAFMs offer unique THz functional components, which could play a significant role in filling the THz technology gap.