Cooperative orbital moments and edge magnetoresistance in monolayer WTe2

We argue that edge electrons in monolayer WTe2 can possess a "cooperative" orbital moment (COM) that critically impacts its edge magnetoresistance behavior. Arising from the cooperative action of both Rashba and Ising spin-orbit coupling, COM quickly achieves large magnitudes (of the order of a few Bohr magnetons) even for relatively small spin-orbit coupling strengths. As we explain, such large COM magnitudes arise from an unconventional cooperative spin canting of edge spins when Rashba and Ising spin-orbit coupling act together. Strikingly, COM can compete with spin moments to produce an unusual anisotropic edge magnetoresistance oriented at an oblique angle. In particular, this competition produces a direction along which B is ineffective at gapping out the edge spectrum, leaving it nearly gapless. As a result, large contrasts in gap sizes appear as B is rotated, granting a giant anisotropic magnetoresistance as large as several million percent at 10 T and low temperature.