Resonant interlayer coupling in NbSe${}_2$-graphite epitaxial moir{é} superlattices

Abstract

Moir{é} heterostructures, created by stacking two-dimensional (2D) materials together with a finite lattice mismatch or rotational twist, represent a new frontier of designer quantum materials. Typically, however, this requires the painstaking manual assembly of heterostructures formed from exfoliated materials. Here, we observe clear spectroscopic signatures of moir{é} lattice formation in epitaxial heterostructures of monolayer (ML) NbSe${}_2$ grown on graphite substrates. Our angle-resolved photoemission measurements and theoretical calculations of the resulting electronic structure reveal moir{é} replicas of the graphite $\ddot{I}€$ states forming pairs of interlocking Dirac cones. Interestingly, these intersect the NbSe${}_2$ Fermi surface at the $\mathbf{k}$-space locations where NbSe${}_2$'s charge-density wave (CDW) gap is maximal in the bulk. This provides a natural route to understand the lack of CDW enhancement for ML-NbSe${}_2$/graphene as compared to a more than four-fold enhancement for NbSe${}_2$ on insulating support substrates, and opens new prospects for using moir{é} engineering for controlling the collective states of 2D materials.

11 pages including supplementary information, 4+5 figures