Quasi-freestanding monolayer heterostructure of graphene and hexagonal boron nitride on Ir(111) with a chiral boundary

TL;DR

This paper reports the synthesis and characterization of a nearly freestanding monolayer heterostructure of graphene and hexagonal boron nitride on Ir(111), highlighting atomically sharp interfaces with chiral boundaries and unique electronic properties.

Contribution

It presents the first synthesis of a nearly freestanding graphene/h-BN hybrid on Ir(111) with atomically sharp, chiral boundaries, combining experimental STM/STS and theoretical DFT analysis.

Findings

Seamless monolayer hybrid with zigzag chiral boundaries

Atomically sharp interface confirmed by STM/STS and DFT

Hybrid exhibits distinct local electronic properties

Abstract

Monolayer lateral heterostructure of graphene and hexagonal boron nitride (h-BNC) has attracted a growing attention mainly due to its tunable band-gap character and unique physical properties at interface. Hereby, we reported the first-time synthesis of a nearly freestanding h-BNC hybrid on a weakly coupled substrate of Ir (111), where graphene and h-BN possessing different surface heights and corrugations formed a perfect monolayer hybrid. With the aid of scanning tunneling microscopy/spectroscopy (STM/STS), we demonstrated that h-BN can patch alongside the boundary of pre-deposited graphene domains and vice versa to form a seamless monolayer hybrid, with the realization of predominant zigzag type chiral boundaries at the interface. Density-functional theory calculations and STM/STS measurements aided us to reveal that this interface between graphene and h-BN were atomically sharp in aspects of the chemical bonding as well as the local electronic property from both theoretical and experimental points of view.