Mesoscopic transport in electrostatically-defined spin-full channels in quantum Hall ferromagnets

摘要

In this work we use electrostatic control of quantum Hall ferromagnetictransitions in CdMnTe quantum wells to study electron transport throughindividual domain walls (DWs) induced at a specific location. These DWs areformed due to hybridization of two counter-propagating edge states withopposite spin polarization. Conduction through DWs is found to be symmetricunder magnetic field direction reversal, consistent with the helical nature ofthese DWs. We observe that long domain walls are in the insulating regime withlocalization length 4 - 6~$\mu$m. In shorter DWs the resistance saturates to anon-zero value at low temperatures. Mesoscopic resistance fluctuations in amagnetic field are investigated. The theoretical model of transport throughimpurity states within the gap induced by spin-orbit interactions agrees wellwith the experimental data. Helical DWs have required symmetry for theformation of synthetic p-wave superconductors. Achieved electrostatic controlof a single helical domain wall is a milestone on the path to theirreconfigurable network and ultimately to a demonstration of braiding ofnon-Abelian excitations.