Estimation of Rectifying Performance for Terahertz Wave in Newly Designed Fe/ZnO/MgO/Fe Magnetic Tunnel Junction.

We fabricated fully epitaxial Fe/ZnO/MgO/Fe magnetic tunnel junctions (MTJs) with low junction resistance-area products (several $\Omega$ $\mu$m$^2$) and conducted a theoretical estimation of square-low rectifying performance for a terahertz electromagnetic wave. Effective current responsivity up to 0.09 A/W at 1 THz was obtained under zero-bias voltage condition at room temperature. The result is approximately half the value of the best result obtained for experiments in semiconductor-based diodes, performed under similar conditions. The study strongly suggests that this MTJ system has a great potential for the rectifying element of the terahertz wave.