Large spin-to-charge conversion at the two-dimensional interface of transition metal dichalcogenides and permalloy

Spin-to-charge conversion is an essential requirement for the implementation of spintronic devices. Recently, monolayers of semiconducting transition metal dichalcogenides (TMDs) have attracted considerable interest for spin-to-charge conversion due to their high spin-orbit coupling and lack of inversion symmetry in their crystal structure. However, reports of direct measurement of spin-to-charge conversion at TMD-based interfaces are very much limited. Here, we report on the room temperature observation of a large spin-to-charge conversion arising from the interface of Ni${}_{80}$Fe${}_{20}$ (Py) and four distinct large area ($\sim 5\times 2$~mm${}^2$) monolayer (ML) TMDs namely, MoS${}_2$, MoSe${}_2$, WS${}_2$, and WSe${}_2$. We show that both spin mixing conductance and the Rashba efficiency parameter (${\lambda }_{IREE}$) scales with the spin-orbit coupling strength of the ML TMD layers. The ${\lambda }_{IREE}$ parameter is found to range between $-0.54$ and $-0.76$ nm for the four monolayer TMDs, demonstrating a large spin-to-charge conversion. Our findings reveal that TMD/ferromagnet interface can be used for efficient generation and detection of spin current, opening new opportunities for novel spintronic devices.