Top (a) and side (b) views of one of the vdW heterostructures of graphene on a monolayer Cr₂Ge₂Te₆. In the unit cell, two C atoms of graphene lie directly above two Te atoms (labeled by dashed circles) of Cr₂Ge₂Te₆. Reprinted with permission from Ref. [18]. Copyright 2015 by the American Physical Society.