Orbitronic terahertz emission from Mo-based nanolayers via the inverse orbital Hall and Rashba–Edelstein effects

Abstract

Rapid advancements in the communications and semiconductor industries have brought about the need to move to higher operating frequencies, with the terahertz (THz) frequency band being prospected as the next frontier for wireless communications and data transfer. Recent work has established that it is possible to harness orbital currents to generate THz radiation from metallic heterostructures comprised of ferromagnetic and transition metals. We demonstrate THz emission from Co/Mo/SiO2 and Co/Au/Mo/SiO2 orbitronic THz emitters (OTEs) via the inverse orbital Hall effect and the inverse orbital Rashba–Edelstein effect and measure the velocity of orbital carriers in Mo. Given the interplay between the various spin and orbital effects in OTEs that allow for interconversions between spin and orbital torque simply by the introduction of nm-thick metallic films, such devices hold significant potential in paving the way for the steady march away from conventional charge-based electronics in the decades to come.