Spatially resolved one-dimensional boundary states in graphene–hexagonal boron nitride planar heterostructures

Abstract

Two-dimensional interfaces between crystalline materials have been shown to generate unusual interfacial electronic states in complex oxides. Recently, a one-dimensional interface has been realized in hexagonal boron nitride and graphene planar heterostructures, where a polar-on-nonpolar one-dimensional boundary is expected to possess peculiar electronic states associated with edge states of graphene and the polarity of boron nitride. Here we present a combined scanning tunnelling microscopy and first-principles theory study of the graphene-boron nitride boundary to provide a first glimpse into the spatial and energetic distributions of the one-dimensional boundary states down to atomic resolution. The revealed boundary states are about 0.6 eV below or above the Fermi level depending on the termination of the boron nitride at the boundary, and are extended along but localized at the boundary. These results suggest that unconventional physical effects similar to those observed at two-dimensional interfaces can also exist in lower dimensions.

Materials design for electrocatalytic carbon capture

“…There are now numerous theoretical studies of different aspects of such interfaces as well as experimental realizations (e.g., Refs. [30][31][32][33][34][35]. We have investigated electrocatalytic CO 2 binding on two possible nanocomposite arrangements: planar stacking 36 and an in-plane, "striped" heteroepitaxial model.…”

Tunneling spectra of graphene on copper unraveled

“…After the prolonged vacuum annealing, irregularly shaped patches with slightly different apparent heights than the surroundings emerge (Fig. 2a, acquired after the first 700 C, 20 min annealing, shows portions of two patches exhibiting a square pattern, along with an adjacent area (upperleft) that shows a linear superstructure with a ~1.1 nm period, which is attributed to the moiré pattern between graphene and Cu(001), 18,19 the predominant post-growth surface termination of the Cu foil 16,19,20 used in the present study. The patches exhibit a sharper contrast in simultaneously acquired STS maps (Fig.…”

“…6 The graphene is n doped due to charge transfer. In our previous work, 15,16 while the STS of CVD graphene on Cu(001) has the two general features (one minimum at and another below E F ), the hexagonal boron nitride (h-BN) grown on the same substrate exhibits STS curves of very similar shapes, casting doubt on the interpretation of the graphene/Cu(001) STS. In our previous work, 15,16 while the STS of CVD graphene on Cu(001) has the two general features (one minimum at and another below E F ), the hexagonal boron nitride (h-BN) grown on the same substrate exhibits STS curves of very similar shapes, casting doubt on the interpretation of the graphene/Cu(001) STS.…”

DARPA neurocomputing

“…An example is the DARPA UPSIDE program that is demonstrating that analog computing and specialized devices, such as memristors, graphene and spin torque oscillators, can perform inference calculations, which may take the form of a neural network, for image processing applications. 9,10,11 This is achieved by using the analog properties of the devices to perform the calculation. The inference operations are mapped to devices in ways in which the physics of the devices perform the computation directly.…”