Current-enhanced broadband THz emission from spintronic devices

TL;DR

This paper introduces a hybrid spintronic and semiconductor THz emitter that significantly enhances broadband THz emission, especially in the lower frequency range, by applying a bias current to combine magnetic and photoconductive effects.

Contribution

It presents a novel current-enhanced hybrid approach that boosts broadband THz emission from spintronic devices, extending their effective frequency range.

Findings

2-3 orders of magnitude enhancement in 0.1-0.5 THz range

Comparable performance at higher frequencies

Demonstrates effective integration of magnetic and semiconductor effects

Abstract

An ultra-broadband THz emitter covering a wide range of frequencies from 0.1 to 10 THz is highly desired for spectroscopy applications. So far, spintronic THz emitters have been proven as one class of efficient THz sources with a broadband spectrum while the performance in the lower frequency range (0.1 to 0.5 THz) limits its applications. In this work, we demonstrate a novel concept of a current-enhanced broad spectrum from spintronic THz emitters combined with semiconductor materials. We observe a 2-3 order enhancement of the THz signals in a lower THz frequency range (0.1 to 0.5 THz), in addition to a comparable performance at higher frequencies from this hybrid emitter. With a bias current, there is a photoconduction contribution from semiconductor materials, which can be constructively interfered with the THz signals generated from the magnetic heterostructures driven by the inverse spin Hall effect. Our findings push forward the utilization of metallic heterostructures-based THz emitters on the ultra-broadband THz emission spectroscopy.