Presentation Information
[3C09]2D THz spintronics: origin and enhancement of spin-to-charge conversion in graphene
*Mary Clare Escaño1, Tien Quang Nguyen2, Elvis Arguelles3, Masahiko Tani1 (1. Research Center for Development of Far-Infrared Region, University of Fukui, 2. Institute for Aqua Regeneration, Shinshu University, 3. The Institute for Solid State Physics, The University of Tokyo)
THz region, lying between the microwave and infrared, remains unexplored due to the lack of efficient sources. Previously, we developed spintronic THz emitters, such as Fe/Pt bilayers. The emission is attributed to spin-current injection from ultrafast laser excitation of FM and transient spin-to-charge conversion (SCC) by inverse spin-hall effect (ISHE) at the NM. However, NMs are precious metals, prompting interest in 2D materials. SCC was recently observed in monolayer graphene (SLG) on Ni-rich permalloy using spin-pumping techniques, though with a small SCC coefficient (~0.002 nm). In this study, we investigated the SCC in Ni/SLG using first-principles method with spin-orbit coupling. The estimated SCC matches experimental value and originates from the inverse Rashba-Edelstein effect (IREE) due to Rashba splitting at Dirac points, which in turn is caused by hybridization with Ni. Based on this, we designed a “bridge” structure that enhances Rashba effects and the SCC efficiency.