Proximity effect between graphene and 2D anti-ferromagnetic insulator α-RuCl3*

Proximity effects attempting to combine electronic properties of graphene with exotic phenomena in other 2D van der Waals materials have been a central focus of condensed matter research for the past decade. To date, much work has been done studying proximity effects between graphene and ferromagnetic insulators, but little is known experimentally about the coupling between graphene and anti-ferromagnetic insulators. We report transport results from proximity devices consisting of graphene and α-RuCl3, a layered anti-ferromagnetic Mott insulator predicted to host a so-called Kitaev quantum spin liquid. Upon cooling the device, the derivative of resistance with temperature shows a peak-dip feature. Depending on the gate voltage, this feature is seen anywhere from 35-50K, much higher than the Neel temperature of 14K. This could indicate a magnetic phase transition in the heterostructure.