Terahertz frequency spectrum analysis with a nanoscale antiferromagnetic tunnel junction

TL;DR

This paper proposes a novel nanoscale antiferromagnetic tunnel junction (ATJ) based method for rapid, low-power spectrum analysis in the terahertz range, enabling miniaturized electronics to analyze signals efficiently.

Contribution

It introduces a new spectrum analysis technique using a tunable nanoscale ATJ that operates at THz frequencies, combining simulation and analytical theory to demonstrate its effectiveness.

Findings

Spectrum analysis over 0.25 THz bandwidth in 25 ns.

ATJ oscillation frequency can be linearly tuned with time.

Method operates near the thermal noise floor for low power signals.

Abstract

A method to perform spectrum analysis on low power signals between 0.1 and 10 THz is proposed. It utilizes a nanoscale antiferromagnetic tunnel junction (ATJ) that produces an oscillating tunneling anisotropic magnetoresistance, whose frequency is dependent on the magnitude of an evanescent spin current. It is first shown that the ATJ oscillation frequency can be tuned linearly with time. Then, it is shown that the ATJ output is highly dependent on matching conditions that are highly dependent on the dimensions of the dielectric tunneling barrier. Spectrum analysis can be performed by using an appropriately designed ATJ, whose frequency is driven to increase linearly with time, a low pass filter, and a matched filter. This method of THz spectrum analysis, if realized in experiment, will allow miniaturized electronics to rapidly analyze low power signals with a simple algorithm. It is also found by simulation and analytical theory that for an ATJ with a 0.09 $\mu$m$^2$ footprint, spectrum analysis can be performed over a 0.25 THz bandwidth in just 25 ns on signals that are at the Johnson-Nyquist thermal noise floor.