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Nanoporous carbon foams (CFs), which are formed by the interconnection of graphene stripes and sp3 hybridized carbon junctions, have attracted great attention owing to their potential applications. However, the structural diversity makes it hard to experimentally gain accurate structural information. By performing first-principles calculations, we propose nanoporous CFs, which are based on the sixfold-wing...
Recently, He et al. succeeded in covalently linking porphines to graphene edges on a Ag(111) substrate by dehydrogenative coupling [Nat. Chem. 9 (1) (2017) 33–38], thus created a new hybrid material with tunable functionalities. Motivated by this work, we further investigate the electron transport properties of three porphine/graphene coupling motifs observed by scanning-probe technology with submolecular...
Based on the nonequilibrium Green's function and density functional theory, a method to investigate the spin-dependent Seebeck effect (SDSE) with consideration of inelastic transport processes is presented. Results show that phonons with lower vibration energy may have more possibilities to contribute thermal drive inelastic currents and affect the SDSE properties. Consideration of inelastic processes...
We investigate the effects of embedded magnetic atoms on the edge states and spin-dependent transport properties of zigzag 6, 6, 12-graphyne nanoribbon (6, 6, 12-Z GYNRs) using non-equilibrium Greens functions combined with density-function theory. The results show that spin splitting occurs when doping magnetic atoms in the natural “holes” of the 6, 6, 12-Z GYNRs. Particularly, the half-metallicity...
The thermal transport properties of phonons in zigzag graphene nanoribbon (ZGNR) modulated by defect and alternating boron-nitride structure (BNS) are studied by nonequilibrium Greens function (NEGF) formalism combined with first-principles calculations of density-functional theory with local density approximation. Our calculations show that the thermal conductance in ZGNR with BNS is higher than...
Carbon foam nanowires (CFNWs), which are mixed sp2/sp3 hybridized microporous one-dimensional structures, have received much attention in the past two decades. In the present work, first-principle and molecular dynamics (MD) calculations revealed that the surface states causes the metallicity of CFNWs with small size, which demonstrates a Dirac cone-like dispersion near Γ in the Brillouin zone, while...
By using nonequilibrium Green's functions in combination with the density functional theory, the spin transport properties of a single-molecule spintronic device are investigated. The computational results show that when the magnetic configuration of the device is set as parallel, the perfect spin-filtering effect can be observed. Especially, this perfect spin-filtering effect is independent of the...
Thermal transport across graphene/hexagonal boron nitride (h-BN) nanoribbon interface is investigated using nonequilibrium molecular dynamics method. It is found that the heat current runs preferentially from the h-BN to graphene domain, which demonstrates pronounced thermal rectification behavior in this heterostructure. The observed phenomena can be attributed to the resonance effect between out-of-plane...
The thermal transport properties of electrons in graphene nanoribbon (GNR) subjected to strain fields are studied by non-equilibrium Green's function approach. The results show that the stretching of the carbon–carbon bond in strained GNR can enhance the ballistic thermal conductance of electrons. The enhancement originates from that the change of C–C bond length can modulate the nearest-neighbour...
By using nonequilibrium Green's functions in combination with the density functional theory, we investigate the transport properties of the supramolecular spin valves made of ferrocene and pristine (p-type or n-type) graphene nanoribbons. The results show that ferrocene adsorption on pristine graphene nanoribbons gives rise to perfect magnetoresistive effect. While for ferrocene adsorption on p-type...
The classical Kirchhoff's superposition law is hard to realize in the molecular scale devices because the coupling between the juxtaposed molecules can lead to constructive or destructive quantum interferences [Vazquez et al. nature nanotechnology 2012, 7, 663; Zhu et al. Phys. Rev. B 2014, 89, 085427]. In view of this, we try to eliminate the quantum interference between the juxtaposed molecules...
The thermal, electrical and thermoelectric properties of zigzag graphene nanoribbon with gold atom chains at the edges have been analyzed carefully by first-principles calculation. The results indicate that, majority of the injected phonons will be scattered by the gold chains, while the electrons can transport smoothly due to the existence of the edge states. As a result, the thermoelectric effect...
The thermoelectric properties of the defective β-graphyne nanoribbons are investigated by using the nonequilibrium Green’s function method. The results show that the thermoelectric properties of β-graphyne nanoribbons can be enhanced observably by introducing defects. The figure of merit of defective β-graphyne nanoribbons can reach 1.64, which is about six times larger than that of perfect β-graphyne...
The thermal transport properties of graphene nanoribbons with cavities are studied by non-equilibrium Green’s function approach. A comparative analysis between in-plane and out-of-plane modes is made. The results show that the quantized thermal-conductance plateau of in-plane modes is wider and not broken in graphene nanoribbon with cavities. Contribution of the out-of-plane modes to the total thermal...
The electronic transport properties of zigzag 6, 6, 12-graphyne nanoribbons (6, 6, 12-Z GYNRs) are investigated by first-principles calculations. The results show that the two bands around the Fermi level of 4-6, 6, 12-ZGYNR are not flat but cambered, which is different from that of zigzag graphene and α-graphyne nanoribbons, and is also different from that of 5-6, 6, 12-ZGYNR. In non-magnetic states,...
The thermal transport properties of graphene nanoribbons (GNRs) with pentagon–heptagon defect (PHD) are studied by using first principles calculations in combination with non-equilibrium Green’s function approach. The results show that the PHD effect on thermal conduction in armchair-oriented GNR is stronger than that in zigzag-oriented GNR. The out-of-plane acoustic mode is almost reflected by the...
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