Broadband terahertz generation via the interface inverse Rashba-Edelstein effect

TL;DR

This paper introduces a novel broadband terahertz emission mechanism based on the interface inverse Rashba-Edelstein effect, demonstrating controllable THz waveforms from engineered heterostructures and revealing potential for versatile THz sources.

Contribution

It presents the first demonstration of broadband THz emission via the interface inverse Rashba-Edelstein effect in metallic heterostructures, enabling controllable and tunable THz waveforms.

Findings

Controllable THz emission waveform (~0.1-5 THz) from Fe/Ag/Bi heterostructures.

Selective superposition of THz radiation with inverse Spin Hall effect emission.

Thickness-dependent emission patterns revealing interface quantum effects.

Abstract

Novel mechanisms for electromagnetic wave emission in the terahertz (THz) frequency regime emerging at the nanometer scale have recently attracted intense attention for the purpose of searching next-generation broadband THz emitters. Here, we report a new mechanism for broadband THz emission, utilizing the interface inverse Rashba-Edelstein effect. By engineering the symmetry of the Ag/Bi Rashba interface, we demonstrate a controllable THz radiation (~0.1-5 THz) waveform emitted from metallic Fe/Ag/Bi heterostructures following photo-excitation. We further reveal that this type of THz radiation can be selectively superimposed on the emission discovered recently due to the inverse Spin Hall effect, yielding a unique film thickness dependent emission pattern. Our results thus offer new opportunities for versatile broadband THz radiation using the interface quantum effects.