A Resonance-Type Terahertz-Frequency Signal Detector Based on an Antiferromagnetic Tunnel Junction

Detection of terahertz-frequency (TF) electromagnetic signals is an important task required for many applications of TF electromagnetic radiation in medicine, security, communications, technology and science. Here we present a theoretical proposal of a novel resonance-type terahertz-frequency signal detector (TFSD) based on an antiferromagnetic tunnel junction (ATJ). The junction is a four-layer structure Pt/AFM/MgO/Pt consisting of two platinum (Pt) layers, a layer of an antiferromagnet (AFM) and the MgO tunneling barrier. When an external bias dc current is flowing in the bottom Pt layer (adjacent to the AFM), it produces TF oscillations of junction's tunneling magnetoresistance that being mixed with an input TF ac current, in turn, leads to the generation of an output dc voltage across the junction. Using a simple electrical model of the TFSD we show that TFSD's output voltage reduces with an increase of the signal frequency, but it can be sufficient for some applications in the frequency range 0.1 - 1 THz (~ 0.4 mV for input power of 1 μW), if the ATJ having thin MgO tunneling barrier (thickness ~ 1 nm) and small cross-sectional area (~ 100×100 nm
²
) is used.