  Proximity effects are one of the pillars of exotic phenomena and
technological applications of two dimensional materials. However, the
interactions nature depends strongly on the materials involved, their
crystalline symmetries, and interfacial properties. Here we used large-scale
first-principle calculations to demonstrate that strain and twist-angle are
efficient knobs to tailor the spin-orbit coupling in graphene transition metal
dichalcogenide heterobilayers. We found that by choosing a twist-angle of 30
degrees, the spin relaxation times increase by two orders of magnitude, opening
a path to improve these heterostructures spin transport capability. Moreover,
we demonstrate that strain and twist angle will modify the relative values of
valley-Zeeman and Rashba spin-orbit coupling, allowing to tune the system into
an ideal Dirac-Rashba regime. These results enable us to envision an answer for
the variability of spin-orbit coupling found in different experiments and have
significant consequences for applications that depend on polycrystallinity,
where grains form at different orientations.
