Wang Ying, Ponomarenko Vadim, Wan Zhong, West Kenneth W, Baldwin Kirk W, Pfeiffer Loren N, Lyanda-Geller Yuli, Rokhinson Leonid P
Department of Physics and Astronomy, Purdue University, West Lafayette, IN, USA.
Ioffe Physico-Technical Institute, Saint-Petersburg, Russia.
Nat Commun. 2021 Sep 7;12(1):5312. doi: 10.1038/s41467-021-25631-2.
Domain walls in fractional quantum Hall ferromagnets are gapless helical one-dimensional channels formed at the boundaries of topologically distinct quantum Hall (QH) liquids. Naïvely, these helical domain walls (hDWs) constitute two counter-propagating chiral states with opposite spins. Coupled to an s-wave superconductor, helical channels are expected to lead to topological superconductivity with high order non-Abelian excitations. Here we investigate transport properties of hDWs in the ν = 2/3 fractional QH regime. Experimentally we found that current carried by hDWs is substantially smaller than the prediction of the naïve model. Luttinger liquid theory of the system reveals redistribution of currents between quasiparticle charge, spin and neutral modes, and predicts the reduction of the hDW current. Inclusion of spin-non-conserving tunneling processes reconciles theory with experiment. The theory confirms emergence of spin modes required for the formation of fractional topological superconductivity.
分数量子霍尔铁磁体中的畴壁是在拓扑不同的量子霍尔（QH）液体边界形成的无隙螺旋一维通道。直观地说，这些螺旋畴壁（hDWs）由两个具有相反自旋的反向传播手征态组成。与s波超导体耦合时，螺旋通道有望导致具有高阶非阿贝尔激发的拓扑超导性。在这里，我们研究了ν = 2/3分数量子霍尔区域中hDWs的输运性质。实验上我们发现，hDWs携带的电流远小于简单模型的预测。该系统的卢廷格液体理论揭示了准粒子电荷、自旋和中性模式之间电流的重新分布，并预测了hDW电流的减小。包含自旋非守恒隧穿过程使理论与实验相符。该理论证实了形成分数量子拓扑超导性所需的自旋模式的出现。
