Operation of a Terahertz Signal Detector Based on an Antiferromagnetic Tunnel Junction in the Presence of Low-Frequency Johnson-Nyquist Noise

In this work, we extend our previous temperature-dependent model of the terahertz signal detector based on an antiferromagnetic tunnel junction and then use the updated model to analyze the noise properties of the detector in the presence of low-frequency Johnson-Nyquist noise. We show that cooling the detector to cryogenic temperatures (~ 4.2 K) results in a significant increase in its output dc voltage and signal-to-noise ratio. This effect is found to be frequency dependent; the maximum improvement in detector performance is reached at a certain frequency (~0.15 THz in our case) due to the interplay between the effect of temperature on the magnetic and electrical parameters of the junction and the matching between the detector and an external electrodynamic system. The developed formalism could be used for the optimization of terahertz signal detectors and other spintronic devices based on antiferromagnets.