Wei Nemin, Huang Chunli, MacDonald Allan H
Department of Physics, The University of Texas at Austin, Austin, Texas 78712, USA.
Phys Rev Lett. 2021 Mar 19;126(11):117203. doi: 10.1103/PhysRevLett.126.117203.
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.
受近期关于单层石墨烯N = 0朗道能级中形成的量子霍尔磁体（QHM）态的非局域输运研究的启发，我们研究了具有不同整数填充因子ν的态之间由栅极控制的结处QHM磁振子的散射。对于ν = 1|-1|1几何结构，我们发现磁振子在结区的电势变化下散射较弱，并且当结缺乏镜面对称性时，散射是手性的。对于ν = 1|0|1几何结构，我们发现如果入射角超过临界值，运动学约束会完全阻止磁振子传输。我们的结果解释了在ν = 1|0|1情况下观察到的非局域电压信号的抑制。我们利用我们的理论提出，在ν = -1|1结处产生的谷波和磁振子可以结合起来，用于探测整数和分数填充因子下QHM态的自旋或谷味结构。
