Helical quantum Hall phase in graphene on SrTiO <sub>3</sub>
Louis Veyrat, Corentin Déprez, Alexis Coissard, Xiaoxi Li, Frédéric Gay, Kenji Watanabe, Takashi Taniguchi, Zheng Han, B. A. Piot, H. Sellier, Benjamin Sacépé
Abstract
Controlling the interactions Near charge neutrality and subject to perpendicular magnetic fields, graphene is expected to become a ferromagnet with edge states not unlike those in two-dimensional topological insulators. Observing this effect experimentally has proven tricky because very large magnetic fields are needed to overcome the effect of electron-electron interactions, which drive the system to competing states. Instead of amping up the field, Veyrat et al. placed their graphene samples on a substrate made out of strontium titanate, which effectively screened the interactions. Transport measurements confirmed the formation of the characteristic edge states. Science , this issue p. 781