  We evidence the possibility for coherent electrical manipulation of the spin
orientation of topologically protected edge states in a low-symmetry quantum
spin Hall insulator. By using a combination of ab-initio simulations,
symmetry-based modeling, and large-scale calculations of the spin Hall
conductivity, it is shown that small electric fields can efficiently vary the
spin textures of edge currents in monolayer 1T'-WTe2 by up to a 90-degree spin
rotation, without jeopardizing their topological character. These findings
suggest a new kind of gate-controllable spin-based device, topologically
protected against disorder and of relevance for the development of topological
spintronics.
