Selective equilibration of spin and valley polarized quantum Hall edge states in graphene

التفاصيل البيبلوغرافية
العنوان: Selective equilibration of spin and valley polarized quantum Hall edge states in graphene
المؤلفون: Amet, F., Wiliams, J. R., Watanabe, K., Taniguchi, T., Goldhaber-Gordon, D.
المصدر: Phys. Rev. Lett. 112, 196601 (2014)
سنة النشر: 2013
المجموعة: Condensed Matter
مصطلحات موضوعية: Condensed Matter - Mesoscale and Nanoscale Physics
الوصف: We report on transport measurements of dual-gated, single-layer graphene devices in the quantum Hall regime, allowing for independent control of the filling factors in adjoining regions. Progress in device quality allows us to study scattering between edge states when the four-fold degeneracy of the Landau level is lifted by electron correlations, causing edge states to be spin and/or valley polarized. In this new regime, we observe a dramatic departure from the equilibration seen in more disordered devices: edge states with opposite spins propagate without mixing. As a result, the degree of equilibration inferred from transport can reveal the spin polarization of the ground state at each filling factor. In particular, the first Landau level is shown to be spin-polarized at half-filling, providing an independent confirmation of a conclusion of Ref.[1]. The conductance in the bipolar regime is strongly suppressed, indicating that co-propagating edge states, even with the same spin, do not equilibrate along PN interfaces. We attribute this behavior to the formation of an insulating nu=0 stripe at the PN interface.
نوع الوثيقة: Working Paper
DOI: 10.1103/PhysRevLett.112.196601
URL الوصول: http://arxiv.org/abs/1307.4408
رقم الأكسشن: edsarx.1307.4408
قاعدة البيانات: arXiv