Terahertz detection based on nonlinear Hall effect without magnetic field

TL;DR

This paper introduces a broadband terahertz photodetector utilizing the nonlinear Hall effect in non-centrosymmetric materials, enabling zero-bias detection with high responsivity based on Berry curvature.

Contribution

It presents a novel zero-bias terahertz detector leveraging the nonlinear Hall effect, with a first-principles approach to evaluate responsivity independent of frequency.

Findings

Weyl semimetal NbP shows high responsivity (~1A/W) for terahertz detection.

The detector operates without external bias and has a fast response speed.

Responsivity is a material property derived from Berry curvature, independent of incident frequency.

Abstract

We propose a method for broadband long-wavelength photodetection using the nonlinear Hall effect in non-centrosymmetric quantum materials. The inherently quadratic relation between transverse current and input voltage at zero magnetic field is used to rectify the incident terahertz or infrared electric field into a direct current, without invoking any diode. Our photodetector operates at zero external bias with fast response speed and has zero threshold voltage. Remarkably, the intrinsic current responsivity due to Berry curvature mechanism is a material property independent of the incident frequency or the scattering rate, which can be evaluated from first-principles electronic structure calculations. We identify the Weyl semimetal NbP for terahertz photodection with large current responsivity reaching $\sim 1$A/W without external bias.