Pressure-induced commensurate stacking of graphene on boron nitride

Abstract

Combining atomically-thin van der Waals materials into heterostructures provides a powerful path towards the creation of designer electronic devices. The interaction strength between neighbouring layers, most easily controlled through their interlayer separation, can have significant influence on the electronic properties of these composite materials. Here, we demonstrate unprecedented control over interlayer interactions by locally modifying the interlayer separation between graphene and boron nitride, which we achieve by applying pressure with a scanning tunnelling microscopy tip. For the special case of aligned or nearly-aligned graphene on boron nitride, the graphene lattice can stretch and compress locally to compensate for the slight lattice mismatch between the two materials. We find that modifying the interlayer separation directly tunes the lattice strain and induces commensurate stacking underneath the tip. Our results motivate future studies tailoring the electronic properties of van der Waals heterostructures by controlling the interlayer separation of the entire device using hydrostatic pressure.

Harmonic model of corrugations of incommensurate two-dimensional layers

“…[14]. Very recent work by Yankowitz et al [35] suggests that sharp contracted ridges at small angles are in fact a tipinduced artifact, not an equilibrium property of the system, consistent with our lack of finding large commensurate domains. 5.…”

“…Depressions are found where half the C atoms rest on top of B atoms, the other half have no substrate top layer atom beneath, and the substrate top layer nitrogens sit below the centers of the graphene-honeycomb rings. The rounded topography, which lacks any sharp features, agrees well with Yankowitz et al's [35] finding that narrow moiré-cell boundaries are only observed in their experiments when graphene is pushed towards the BN substrate by an STM tip.…”

Probing the nanoscale origin of strain and doping in graphene-hBN heterostructures

“…However, the increase in charge density in our case does not coincide with the maximum strain, and there are no defect signatures in the Raman data. Ruling out these possibilities, the charge density features could be caused by modulation of the graphene-hBN interaction near the cavity edge, possibly due to varying interlayer separation [43] or edge potentials at hBN edges. [44]…”

Tunable magnetism of a single-carbon vacancy in graphene

“…The interaction between the localized  and  states, which depends on the local configuration of graphene, determines the magnetism of the single-carbon vacancy in graphene 6,8,9,11,12,15,16 . Previously, it was demonstrated that the STM tip can generate an out-of-plane displacement on graphene through a finite Van de Waals force [25][26][27][28] . Here we show that it is possible to generate out-of-plane lattice deformation around the 5 monovacancy and, consequently, tune interactions between the localized  and  states by using the STM tip.…”