Transport Anisotropy in One-dimensional Graphene Superlattice in the High Kronig-Penney Potential Limit

One-dimensional graphene superlattice subjected to strong Kronig-Penney (KP) potential is promising for achieving electron lensing effect, while previous studies utilizing the modulated dielectric gates can only yield a moderate, spatially dispersed potential profile. Here, we realize high KP potential modulation of graphene via nanoscale ferroelectric domain gating. Graphene transistors are fabricated on PbZr${}_{0.2}$Ti${}_{0.8}$O${}_3$ back-gates patterned with periodic, 100-200 nm wide stripe domains. Due to band reconstruction, the h-BN top-gating induces satellite Dirac points in samples with current along the superlattice vector $\widehat{s}$, a feature absent in samples with current perpendicular to $\widehat{s}$. The satellite Dirac point position scales with the superlattice period ($L$) as $\propto L^{\beta }$, with $\beta =-1.18\pm 0.06$. These results can be well explained by the high KP potential scenario, with the Fermi velocity perpendicular to $\widehat{s}$ quenched to about 1% of that for pristine graphene. Our study presents a promising material platform for realizing electron supercollimation and investigating flat band phenomena.