Anisotropic Electronic Transport in Strain Superlattices in Graphene

Strain superlattices in two-dimensional van der Waals materials can modify the electronic band structure via valley-polarized pseudomagnetic fields. In this talk, we report low temperature charge transport measurements on a graphene strain superlattice (SL) generated by stacking graphene on a self-assembly of dielectric nanospheres (NS). Previously [1], strain-tunable dips were observed in the two-probe conductance of these graphene SLs, as a consequence of SL miniband effects. We now report observations of anisotropies in the Hall and non-local transport characteristics of these graphene-NS systems. This anisotropic transport behavior might indicate an underlying symmetry breaking and lifting of the valley degeneracy in these systems. <br/>[1] Y. Zhang et al, npj 2D Materials and Applications 2, 31 (2018) <br/>The authors acknowledge the support of NSF-MRSEC under award no. DMR-1720633.