Terahertz-Frequency Spin Hall Auto-oscillator Based on a Canted Antiferromagnet

A lack of compact, tunable sources of coherent THz-frequency electromagnetic signals is a fundamental problem in modern microwave/terahertz technology. The authors propose a THz signal generator based on the spin Hall effect in a thin film bilayer: a platinum layer driven by dc current, plus a layer of a canted dielectric antiferromagnet (AFM) with a small net magnetization. Precession of magnetization of the AFM caused by an external spin current produces THz electromagnetic radiation. The power of this signal can exceed 1\textmu{}W, and increases with increasing frequency; however, the achievable density of the external spin current limits the maximum output frequency and power.