Out-of-plane spin-to-charge conversion at low temperatures in graphene/MoTe2 heterostructures

Multi-directional spin-to-charge conversion-in which spin polarizations with different orientations can be converted into a charge current in the same direction-has been demonstrated in low-symmetry materials and interfaces. This is possible because, in these systems, spin-to-charge conversion can occur in unconventional configurations in which charge current, spin current, and polarization do not need to be mutually orthogonal. Here, we explore, in the low temperature regime, the spin-to-charge conversion in heterostructures of graphene with the low-symmetry 1T' phase of MoTe2. First, we observe the emergence of charge conversion for out-of-plane spins at temperatures below 100 K. This unconventional component is allowed by the symmetries of both MoTe2 and graphene and likely arises from spin Hall effect in the spin-orbit proximitized graphene. Moreover, we examine the low-temperature evolution of non-local voltage signals arising from the charge conversion of the two in-plane spin polarizations, which have been previously observed at higher temperature. As a result, we report omni-directional spin-to-charge conversion-for all spin polarization orientations-in graphene/MoTe2 heterostructures at low temperatures.

Automated summary

Multi-directional spin-to-charge conversion has been demonstrated in low-symmetry materials and interfaces, where spin polarizations can be converted into a charge current in the same direction regardless of their orientations. In this study, we investigate the spin-to-charge conversion in graphene/MoTe2 heterostructures at low temperatures. We observe unconventional charge conversion for out-of-plane spins and the evolution of non-local voltage signals arising from in-plane spin polarizations.