Increasing the Efficiency of a Spintronic THz Emitter Based on WSe2/FeCo

Abstract

We report an increase in terahertz (THz) radiation efficiency due to FeCo/WSe2 structures in the reflection geometry. This can be attributed to an absorption increase in the alloy FeCo layer at the input FeCo/WSe2 interface due to constructive interference, as well as to the backward transport of hot carriers from FeCo to WSe2. In contrast to the transmission geometry, the THz generation efficiency in the reflection is much less dependent on the magnetic layer thickness. Our results suggest a cheap and efficient way to improve the characteristics of THz spintronic emitters with the conservation of a full set of their important properties.

Atomic‐Layer Controlled Transition from Inverse Rashba–Edelstein Effect to Inverse Spin Hall Effect in 2D PtSe2 Probed by THz Spintronic Emission

“…[24][25][26] They present several advantages compared to other THz sources such as broadband THz emission, high efficiency, and easy control of radiation parameters. To date, very few 2D materials have been incorporated in THz spintronic emitters [27][28][29][30] and they all exhibit the 1H crystal structure which is not favorable to convert in-plane polarized spins into charge currents. Indeed, the combination of inversion symmetry breaking and strong SOC forces the spin of electrons with finite momentum to be out-of-plane.…”

High Efficiency and Flexible Modulation of Spintronic Terahertz Emitters in Synthetic Antiferromagnets

“…The parameter of the spin Hall angle θ SH reflects the spin-to-charge conversion efficiency of the NM layer, which is related to the spin–orbit coupling interaction. − Apparently, the NM layer plays a key role in the laser-excited THz emission process, and materials with a high θ SH are expected. Various NM layer materials with strong spin–orbit coupling, such as nonmagnetic heavy metals, − antiferromagnets, − two-dimensional materials, − and topological insulators, − have been experimentally demonstrated to be able to generate strong THz signals. − The THz emission process in STEs is complex and involves various successive effects including spin generation, spin diffusion, spin decoherence, and spin–charge conversion. The layer structure and film quality also play a crucial role in determining the efficiency of THz emission. ,− Beigang et al have conducted investigations in Fe/Pt bilayers to understand the different roles of layer thickness, growth condition, substrate choice, and geometrical arrangement in the THz emission process based on the ISHE-based mechanism.…”

An interplay between optical rectification and transient photocurrent effect on THz pulse generation from bulk MoS2 layered crystal

“…Transition metal dichalcogenides (TMDs) are van der Waals' layered materials, which can be processed in monolayer or processing devices working in the realm of terahertz (THz) [12,13]. In the last few years, they have also been shown as potential candidates for THz generation [14,15], both in the bulk [16][17][18][19][20] as well as the monolayer forms [21,22], and also in spintronic heterostructures [23,24]. Rapidly growing applications of THz science and technology [25,26] have also led to intense research on materials and material structures for understanding various fundamental processes mediated at THz energy.…”