Resonant Interlayer Coupling in NbSe2‐Graphite Epitaxial Moiré Superlattices

TL;DR

This paper shows how moiré superlattices formed by stacking niobium diselenide and graphite can influence electronic properties and collective states in 2D materials.

Contribution

The study reveals moiré replica formation and interlayer coupling in epitaxial NbSe2-graphite heterostructures using experimental and theoretical methods.

Findings

Moiré replicas of graphite π states form interlocking Dirac cones intersecting NbSe2's Fermi surface.

The coupling explains the lack of CDW enhancement in NbSe2 on graphene compared to insulating substrates.

Moiré engineering is proposed as a route to control collective states in 2D materials.

Abstract

Moiré heterostructures, created by stacking 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, clear spectroscopic signatures of moiré lattice formation in epitaxial heterostructures of monolayer (ML) NbSe2 grown on graphite substrates are observed. Angle‐resolved photoemission measurements and theoretical calculations of the resulting electronic structure reveal moiré replicas of the graphite π states forming pairs of interlocking Dirac cones. Interestingly, these intersect the NbSe2 Fermi surface at the k‐space locations where NbSe2'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‐NbSe2/graphene as compared to a more than fourfold enhancement for NbSe2 on insulating support substrates, and opens new prospects for using moiré engineering for controlling the collective states of 2D materials.

Combining angle‐resolved photoemission spectroscopy and density functional theory derived calculations, this work reveals strong interlayer coupling and moiré replicas of the graphite π states in molecular‐beam epitaxy grown van der Waals heterostructures of monolayer‐NbSe2/graphite, with implications for its collective phases that form.

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