Broadband Terahertz Generation via the Interface Inverse Rashba-Edelstein Effect

TLDR

Novel mechanisms for electromagnetic wave emission in the terahertz frequency regime at the nanometer scale have attracted intense attention as a route to next‑generation broadband THz emitters. Here, we report broadband THz emission that exploits the interface inverse Rashba–Edelstein effect. The authors engineered the Ag/Bi Rashba interface in Fe/Ag/Bi heterostructures, enabling controllable 0.1–5 THz emission upon photoexcitation, and showed that this radiation can be selectively superimposed on inverse spin Hall effect emission, producing a film‑thickness‑dependent pattern. The study demonstrates versatile broadband (0.1–5 THz) emission from Fe/Ag/Bi heterostructures via the interface inverse Rashba–Edelstein effect, which can be combined with inverse spin Hall emission to yield a thickness‑dependent pattern, opening new opportunities for broadband THz sources.

Abstract

Novel mechanisms for electromagnetic wave emission in the terahertz 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 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 photoexcitation. 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.