▎ 摘　　要

Motivated by recent nonlocal transport studies of quantum-Hall-magnet (QHM) states formed in monolayer graphene's N = 0 Landau level, we study the scattering of QHM magnons by gate-controlled junctions between states with different integer filling factors nu. For the nu = 1 vertical bar-1 vertical bar 1 geometry we find that magnons are weakly scattered by electric potential variation in the junction region, and that the scattering is chiral when the junction lacks a mirror symmetry. For the nu = 1 vertical bar 0 vertical bar 1 geometry, we find that kinematic constraints completely block magnon transmission if the incident angle exceeds a critical value. Our results explain the suppressed nonlocal-voltage signals observed in the nu = 1 vertical bar 0 vertical bar 1 case. We use our theory to propose that valley waves generated at nu = -1 vertical bar 1 junctions and magnons can be used in combination to probe the spin or valley flavor structure of QHM states at integer and fractional filling factors.