Tailoring Symmetry Breaking in Engineered van der Waals Superlattices

Abstract

ABSTRACT Superlattice engineering in van der Waals (vdW) heterostructures (e.g., by moiré engineering) provides a powerful platform for designing electronic bands and realizing correlated and topological quantum phenomena. Here, we pioneer a scheme to tailor superpotentials based on intrinsic substrate electronic orders. We show that this establishes a robust, self‐aligned, and highly versatile route to band‐structure control, as we demonstrate in graphene by engineering two distinct, nearly commensurate superlattices using the charge density waves (CDWs) of 1T‐NbSe 2 . In these superlattices, the graphene's Dirac cones are folded either to the ‐point or to the K‐points of the mini‐Brillouin zone (mBZ). Using scanning tunneling microscopy, we observe that the ‐folded system preserves symmetry, while the K‐folded system exhibits symmetry breaking. Combining density functional theory with an interlayer interaction model, we reveal that this difference is not electronically driven but originates from a structural instability. Our work establishes superlattice engineering for designer quantum states and unveils a structural mechanism for controlled emergent symmetry breaking.