  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 $\hat{s}$, a feature absent in
samples with current perpendicular to $\hat{s}$. 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 $\hat{s}$ 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.
