The equilibration dynamics of spin-polarized quantum Hall edges at graphene p-n junction

The Understanding of equilibration dynamics of quantum Hall (QH) edges is essential to realize an electron interferometer, which has the potential to exhibit fractional statistics and quantum entanglement. Recently, graphene pn junction with spin-valley polarized QH edges showed an ideal platform for an electron interferometer. However, the interplay of different scattering mechanisms in equilibration of polarized QH edges at the graphene pn junction remain elusive. In this report, we have carried out the conductance together with shot noise measurements for symmetry broken QH edges co-propagating along a pn junction. The pn junction was realized in a dual
graphite gated hexagonal boron nitride (hBN) encapsulated graphene device. Earlier studies with unpolarized QH edges showed incoherent processes as the dominant scattering mechanism for mode mixing. However, Our results reveal that the mode mixing dynamics of the polarized QH edges are much more intricate depending on the spin sequence of QH edges. A complete crossover from incoherent to fully coherent scattering regime was observed by tuning the number of participating polarized QH edges at the pn junction, which will pave the way to design the electron quantum optics experiments based on polarized QH edges of graphene.