Inverse Rashba-Edelstein THz emission modulation induced by ferroelectricity in CoFeB/PtSe2/MoSe2//LiNbO3 systems

TL;DR

This paper demonstrates how ferroelectric polarization in a heterostructure modulates Terahertz emission via the inverse Rashba-Edelstein effect, advancing low-energy spintronic THz sources.

Contribution

It introduces a ferroelectric-controlled heterostructure for modulating THz emission through interfacial spin-to-charge conversion mechanisms.

Findings

Ferroelectric polarization direction significantly modulates THz emission.

Interfacial spin-to-charge conversion is mediated by the inverse Rashba-Edelstein effect.

Band structure calculations support experimental modulation results.

Abstract

Spintronic Terahertz emitters, based on optically triggered spin-to-charge interconversion processes, have recently emerged as novel route towards compact and efficient THz sources. Yet, the next challenge for further technologically-relevant devices remains to modulate the emission, with low-energy consumption operation. To this aim, ferroelectric materials coupled to active spin-orbit layers such as two-dimensional transition metal dichalcogenides are suitable candidates. In this work, we present the realization of a large area heterostructure of CoFeB/PtSe2/MoSe2 on a bi-domain LiNbO3 substrate. Using THz time-domain spectroscopy, we show that the ferroelectric polarization direction induces a sizeable modulation of the THz emission. We rationalise these experimental results by using band structure and spin accumulation calculations that are consistent with an interfacial spin-to-charge conversion mediated by inverse Rashba-Edelstein effect at the MoSe2/PtSe2 interface and being tuned by ferroelectricity in the adjacent LiNbO3 surface. This work points out the relevance of field effect spin-orbit architectures for novel THz technologies.