The Impact of Temperature on the Performance of an Active Terahertz-Frequency Signal Detector Based on an Antiferromagnetic Tunnel Junction

We analyze the performance of an active terahertz (THz)-frequency signal detector based on an antiferromagnetic tunnel junction (ATJ) Pt/Ir ${}_{0.2}$ Mn ${}_{0.8}$ /MgO/Pt in a wide temperature range $T = 4.2$ –300 K. Assuming that the geometric parameters of the ATJ depend on temperature due to the standard thermal expansion, and using usual thermal dependencies for the ATJ resistance-area product and tunneling anisotropic magnetoresistance (TAMR) ratio, we show that the output dc voltage of the detector operating in the frequency range of 0.1–1 THz increases by 50%–70% as the temperature decreases from 300 to 4.2 K. In addition, the cooling of the detector results in a substantial reduction of the low-frequency Johnson-Nyquist noise, and a corresponding increase of the detector signal-to-noise ratio (SNR) (up to 20), as well as in the reduction of the minimum detectable power of the detector (to 1 pW or less). The detector characteristics reach their optimal values near the temperature of $T \simeq 10$ K and frequency of $f \approx 0.15$ THz due to the interplay between the inertial properties of the detector, and its impedance-matching conditions. The developed formalism can be used for the optimization of practical parameters of ATJ-based spintronic devices.