Polarization-selective equilibration and quantum interference in graphene-based quantum Hall edge states

Abstract

Quantum Hall (QH) edge states in two-dimensional electron gas systems have drawn attention as potential carriers of quantum information, owing to their chiral ballistic nature, arising from Landau level formation under a strong perpendicular magnetic field. They remain stable even in the presence of material disorder, making them ideal for phase-sensitive measurements like QH interferometry. We report the equilibration processes between electron waves in spin and valley polarized QH edge states, particularly in a four-terminal measurement configuration. We compare experimental results with theoretical estimations based on the Landauer formula, taking into account selective equilibration depending on spin polarization. Furthermore, quantum interference in co-propagating QH edge states is investigated, elucidating how factors such as magnetic fields, voltage bias, and gate configurations influence quantum phase. The research offers insights into the controllability of interactions between QH edge states, vital for harnessing the potential of graphene in QH interferometers and quantum information processing.