Visualizing In‐Plane Junctions in Nitrogen‐Doped Graphene

Bouatou, Mehdi; Lorentzen, Aleksander Bach; Ngo, Huu Thoai; Girard, Yann; Repain, Vincent; Bellec, Amandine; Rousset, Sylvie; Brandbyge, Mads; Dappe, Yannick J.

doi:10.1002/adfm.202208048

Cited by 4 publications

(13 citation statements)

References 42 publications

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“…Perhaps the simplest examples are side-coupled quantum dots − and magnetic break junctions. − More complex examples include scanning tunneling microscopy of magnetic atoms, − small molecules, − and more recently graphene-like nanostructures − and molecular chains. , Finally, junctions comprising strongly correlated nanostructures can be approximately mapped onto embedded impurity models. − In all these cases, a controlled theoretical treatment is challenging because numerical methods able to reliably access the correlated regime of nonequilibrium quantum impurity models are typically either limited in the level of detail in their description of the baths, especially out of equilibrium, or limited in accuracy by the need to go to high perturbation order (see the Supporting Information). As a result, theoretical work focuses on aspects of the weakly correlated regime − or is confined to single- or few-channel correlated transport. − …”

Section: The Systemmentioning

confidence: 99%

Shaping Electronic Flows with Strongly Correlated Physics

Erpenbeck,

Gull,

Cohen

2023

Nano Lett.

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Nonequilibrium quantum transport is of central importance in nanotechnology. Its description requires the understanding of strong electronic correlations that couple atomic-scale phenomena to the nanoscale. So far, research in correlated transport has focused predominantly on few-channel transport, precluding the investigation of cross-scale effects. Recent theoretical advances enable the solution of models that capture the interplay between quantum correlations and confinement beyond a few channels. This problem is the focus of this study. We consider an atomic impurity embedded in a metallic nanosheet spanning two leads, showing that transport is significantly altered by tuning only the phase of a single local hopping parameter. Furthermore�depending on this phase� correlations reshape the electronic flow throughout the sheet, either funneling it through the impurity or scattering it away from a much larger region. This demonstrates the potential for quantum correlations to bridge length scales in the design of nanoelectronic devices and sensors.

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Section: The Systemmentioning

confidence: 99%

Shaping Electronic Flows with Strongly Correlated Physics

Erpenbeck,

Gull,

Cohen

2023

Nano Lett.

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“…In this frame, the LDA exchange-correlation energy is calculated using the efficient multi-center weighted exchange-correlation density approximation [17,18]. Optimized basis sets for C, O and Al have been used, in agreement with previous calculations [19][20][21]. Hence, we have considered a 4 × 4 layer of graphene, with periodicity in the xy-plane, and an AlO 2 molecule on top.…”

Section: Theoretical Characterization Of Al/graphene and Alox/graphen...mentioning

confidence: 99%

Graphene/aluminum oxide interfaces for nanoelectronic devices

Vu,

Bubendorff,

Mouafo

et al. 2023

Electron. Struct.

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In this work, we study theoretically and experimentally graphene / aluminum oxide interfaces as 0D/2D interfaces for quantum electronics as the nature of the interface is of paramount importance to understand the quantum transport mechanism. Indeed, the electronic transport is driven either by a channel arising from a strong hybridization at the interface, or by tunneling across a van der Waals interface, with very different electric characteristics. By combining electronic spectroscopy and scanning microscopy with Density Functional Theory calculations, we show that the interface is of weak and van der Waals nature. Quantum transport measurements in a single electron transistor confirm this result. Our results provide a first insight into the interfacial properties van der Waals materials based single electron device, and the key role played by the control of the interface states. The weak van der Waals coupling reported is promising for single electron device, where the control of the environmental charges is known to be a key challenge towards applications. Moreover, the unique vertical device architecture, enabled by the dual role of graphene including its vertical electric field transparency, opens the doors for a new class of single electron devices with higher scaling capability and functionalities. This work paves the way to new atomic environment control in single electron device.

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“…This, furthermore, gives rise to a

-system of electrons at the Fermi-level, which is well-described by a widely used

-model. Recently, it was shown how it may be possible to introduce patterns of N-doped regions on graphene by using a molecular overlayer mask of

-molecules in the

-ion implantation, enabling a spatial doping control down to the nano-meter scale [ 14 ]. In Figure 1 A, we show Scanning Tunneling Microscopy (STM) images of a

overlayer mask on graphene.…”

Section: Introductionmentioning

confidence: 99%

“…When doping graphene in the lab, the different concentrations of nitrogen are implanted by first covering parts of the graphene with a C

mask, then bombarding the surface with nitrogen, yielding a 60% reduction in nitrogen implantation under the mask [ 14 ]. This gives a potential profile that corresponds to the shape of the covering layer when the C

is removed from the surface by sweeping the STM tip.…”

Section: Introductionmentioning

confidence: 99%

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Quantum Transport in Large-Scale Patterned Nitrogen-Doped Graphene

Lorentzen,

Bouatou,

Chacon

et al. 2023

Nanomaterials

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It has recently been demonstrated how the nitrogen dopant concentration in graphene can be controlled spatially on the nano-meter scale using a molecular mask. This technique may be used to create ballistic electron optics-like structures of high/low doping regions; for example, to focus electron beams, harnessing the quantum wave nature of the electronic propagation. Here, we employ large-scale Greens function transport calculations based on a tight-binding approach. We first benchmark different tight-binding models of nitrogen in graphene with parameters based on density functional theory (DFT) and the virtual crystal approximation (VCA). Then, we study theoretically how the random distribution within the masked regions and the discreteness of the nitrogen scattering centers impact the transport behavior of sharp n−p and n−n′ interfaces formed by different, realistic nitrogen concentrations. We investigate how constrictions for the current can be realized by patterned high/low doping regions with experimentally feasible nitrogen concentrations. The constrictions can guide the electronic current, while the quantized conductance is significantly washed out due to the nitrogen scattering. The implications for device design is that a p−n junction with nitrogen corrugation should still be viable for current focusing. Furthermore, a guiding channel with less nitrogen in the conducting canal preserves more features of quantized conductance and, therefore, its low-noise regime.

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Visualizing In‐Plane Junctions in Nitrogen‐Doped Graphene

Cited by 4 publications

References 42 publications

Shaping Electronic Flows with Strongly Correlated Physics

Shaping Electronic Flows with Strongly Correlated Physics

Graphene/aluminum oxide interfaces for nanoelectronic devices

Quantum Transport in Large-Scale Patterned Nitrogen-Doped Graphene

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