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 ν. For the ν=1|-1|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 ν=1|0|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 ν=1|0|1 case. We use our theory to propose that valley waves generated at ν=-1|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.
|Journal||Physical Review Letters|
|State||Published - Mar 18 2021|
Bibliographical noteFunding Information:
We acknowledge helpful interactions with Hailong Fu, Andrea Young, Haoxin Zhou, and Jun Zhu. This work is supported by DOE BES Grant No. DE- FG02-02ER45958 and by Welch Foundation Grant No. TBF1473. N. W was partially supported by a Graduate School Continuing Fellowship.
© 2021 American Physical Society.
ASJC Scopus subject areas
- Physics and Astronomy (all)