Structured Graphene Devices for Mass Transport

Barreiro, Amelia; Rurali, Riccardo; Hernández, Eduardo; Bachtold, Adrian

doi:10.1002/smll.201001916

Cited by 24 publications

(34 citation statements)

References 30 publications

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“…The kinetic equation follows by substituting the probability current given in Equation (6) into the continuity Equation (4). One obtains the Fokker-Planck equation for the evolution of the probability density in γ-space…”

Section: Mesoscopic Dynamics Of Small-scale Systemsmentioning

confidence: 99%

“…Moreover, the description is performed in terms of average values not accounting for the presence of fluctuations. Whereas the linear approximation holds for transport processes such as heat conduction and mass diffusion, even in the presence of large or very large gradients [4][5][6], it is not appropriate to OPEN ACCESS describe activated processes in which the system is intrinsically nonlinear. Small systems [7], such as an RNA molecule subjected to an external force [8], in which fluctuations and nonlinearities can be very important, are beyond the scope of this theory.…”

Section: Introductionmentioning

confidence: 99%

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Mesoscopic Thermodynamics for the Dynamics of Small-Scale Systems

Rubı́

2015

Entropy

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Abstract:We analyze the mesoscopic dynamics of small-scale systems from the perspective of mesoscopic non-equilibrium thermodynamics. The theory obtains the Fokker-Planck equation as a diffusion equation for the probability density of the mesoscopic variables and the nonlinear relationships between activation rates and affinities proper of activated processes. The situations that can be studied with this formalism include, among others, barrier crossing dynamics and non-linear transport in a great variety of systems. We, in particular, consider the cases of single-molecule stretching and activated processes in small systems.

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Section: Mesoscopic Dynamics Of Small-scale Systemsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Mesoscopic Thermodynamics for the Dynamics of Small-Scale Systems

Rubı́

2015

Entropy

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“…To achieve the uniform Au distribution which is our goal we perform a low temperature current anneal that redistributes and then quenches the Au configuration. Low temperature post-growth annealing is typical in the synthesis of dilute magnetic semiconductors, to evenly distribute magnetic ions [15,16].Current annealing (see supplementary information) induces diffusive migration of Au on graphene [17]. This shifts the charge neutrality point by δV bg = −8.4 V making graphene arXiv:1607.06893v1 [cond-mat.mes-hall]…”

mentioning

confidence: 99%

“…Current annealing (see supplementary information) induces diffusive migration of Au on graphene [17]. This shifts the charge neutrality point by δV bg = −8.4 V making graphene arXiv:1607.06893v1 [cond-mat.mes-hall]…”

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confidence: 99%

Rashba Interaction and Local Magnetic Moments in a Graphene-BN Heterostructure Intercalated with Au

et al. 2016

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We intercalate a van der Waals heterostructure of graphene and hexagonal Boron Nitride with Au, by encapsulation, and show that Au at the interface is two dimensional. A charge transfer upon current annealing indicates redistribution of Au and induces splitting of the graphene bandstructure. The effect of in plane magnetic field confirms that splitting is due to spin-splitting and that spin polarization is in the plane, characteristic of a Rashba interaction with magnitude approximately 25 meV. Consistent with the presence of intrinsic interfacial electric field we show that the splitting can be enhanced by an applied displacement field in dual gated samples. Giant negative magnetoresistance, up to 75%, and a field induced anomalous Hall effect at magnetic fields < 1 T are observed. These demonstrate that hybridized Au has a magnetic moment and suggests the proximity to formation of a collective magnetic phase. These effects persist close to room temperature.Spin orbit coupling in graphene is induced by hybridization with heavy metals [1]. This has been achieved by intercalation of graphene using e.g. Au, which produces a Rashba interaction ∼ 100 meV [2], and Pb [3], on metallic substrates. We intercalate Au into a heterostructure of graphene and dielectric hexagonal Boron Nitride (hBN), and report spin-splitting of the graphene bands observed in quantum oscillations on an insulating substrate, a crucial requirement for applications. The Rashba interaction is large (25 meV) for samples intercalated with 0.1 monolayers (ML) of Au, but is modulated by modest electric fields, thereby highlighting the requirement of hybridization with spin-split Au d-electrons [2]. We observe large negative magnetoresistance, up to 75%, indicating Au ions form magnetic moments and an anomalous Hall effect suggests the possible formation of a collective magnetic phase. The combination of Rashba interaction, magnetic moments and electric field control of the density, is akin to dilute magnetic semiconductors [4], and in a Dirac material opens a route toward electric field control of magnetism and engineering topological magnetic states such as the quantum anomalous Hall effect [5,6].The van der Waals interaction can create an atomically clean interface between stacked two-dimensional (2D) crystals [7]; therefore, it can be considered organizing principle for atoms or molecules at a hetero-interface [8]. Here, we use the van der Waals interaction to cleanly intercalate Au between graphene and hBN and to induce strong hybridization between graphene and Au. We intercalate graphene-hBN heterostructures by depositing 0.1-0.5 nominal ML of Au onto freshly cleaved hBN on SiO 2 in ultra high vacuum. Au decorated hBN is used as the substrate onto which a separately prepared graphene/hBN (thickness ≈ 20 nm) is transferred, the structure is illustrated in Fig. 1a. The stack is etched and metallic contacts are formed at the exposed edges of graphene [9]. Following thermal annealing the heterostructure is flat with root mean square roughness of 0....

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“…We propose to exploit electromigration as an efficient and easily controllable method to drive the directed transport of adsorbates on graphene. Very recently, and for the first time, the efficient electromigration of metallic clusters/atoms on graphene has been demonstrated experimentally [10]. In the current work, however, we focus on a different class of adsorbates (perhaps more relevant from the perspective of chemical functionalization) -atoms or molecules covalently bound to graphene.…”

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confidence: 99%

Adsorbate Transport on Graphene by Electromigration

Solenov

Velizhanin

2012

Phys. Rev. Lett.

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Chemical functionalization of graphene holds promise for various applications ranging from nanoelectronics to catalysis, drug delivery, and nanoassembly. In many applications it is important to be able to transport adsorbates on graphene in real time. We propose to use electromigration to drive the adsorbate transport across the graphene sheet. To assess the efficiency of electromigration, we develop a tight-binding model of electromigration of an adsorbate on graphene and obtain simple analytical expressions for different contributions to the electromigration force. Using experimentally accessible parameters of realistic graphene-based devices as well as electronic structure theory calculations to parametrize the developed model, we argue that electromigration on graphene can be efficient. As an example, we show that the drift velocity of atomic oxygen covalently bound to graphene can reach ~1 cm/s.

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Structured Graphene Devices for Mass Transport

Cited by 24 publications

References 30 publications

Mesoscopic Thermodynamics for the Dynamics of Small-Scale Systems

Mesoscopic Thermodynamics for the Dynamics of Small-Scale Systems

Rashba Interaction and Local Magnetic Moments in a Graphene-BN Heterostructure Intercalated with Au

Adsorbate Transport on Graphene by Electromigration

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