Mechanical properties and thermal conductivity of graphitic carbon nitride: A molecular dynamics study

Graphitic carbon nitride nanosheets are among 2D attractive materials due to presenting unusual physicochemical properties.Nevertheless, no adequate information exists about their mechanical and thermal properties. Therefore, we used classical molecular dynamics simulations to explore the thermal conductivity and mechanical response of two main structures of single-layer triazine-basedg-C3N4 films.By performing uniaxial tensile modeling, we found remarkable elastic modulus of 320 and 210 GPa, and tensile strength of 47 GPa and 30 GPa for two different structures of g-C3N4sheets. Using equilibrium molecular dynamics simulations, the thermal conductivity of free-standing g-C3N4 structures were also predicted to be around 7.6 W/mK and 3.5 W/mK. Our study suggests the g-C3N4films as exciting candidate for reinforcement of polymeric materials mechanical properties

Sum rule for transport in a Luttinger liquid with long range interaction in the presence of an impurity

We show that the non-linear dc transport in a Luttinger liquid with interaction of finite range in the presence of an impurity is governed by a sum rule which causes the charging energy to vanish.Comment: 5 pages, RevTeX, 1 figure, to be published in Europhysics Letter

Transport through a one-dimensional quantum dot

We examine the effects of long-range interactions in a quantum wire with two impurities. We employ the bosonization technique and derive an effective action for the system. The effect of the long-range interaction on the charging energy and spectral properties of the island formed by the impurities and the linear transport is discussed.Comment: 7 pages, 2 figure

Frequency scaling of photo-induced tunneling

The DC current-voltage characteristics, induced by a driving electric field with frequency Omega, of a one dimensional electron channel with a tunnel barrier is calculated. Electron-electron interaction of finite-range is taken into account. For intermediate interaction strengths, the non-linear differential conductance shows cusp-like minima at bias voltages integer multiples of hbar Omega / e that are a consequence of the finite non-zero range of the interaction but are independent of the shape of the driving electric field. However, the frequency-scaling of the photo-induced current shows a cross-over between Omega^{-1} and Omega^{-2}, and depends on the spatial shape of the driving field and the range of the interaction.Comment: 7 pages, EURO-TeX, 3 figures, to appear in Europhysics Letter

Structural fluctuations and quantum transport through DNA molecular wires: a combined molecular dynamics and model Hamiltonian approach

Charge transport through a short DNA oligomer (Dickerson dodecamer) in presence of structural fluctuations is investigated using a hybrid computational methodology based on a combination of quantum mechanical electronic structure calculations and classical molecular dynamics simulations with a model Hamiltonian approach. Based on a fragment orbital description, the DNA electronic structure can be coarse-grained in a very efficient way. The influence of dynamical fluctuations arising either from the solvent fluctuations or from base-pair vibrational modes can be taken into account in a straightforward way through time series of the effective DNA electronic parameters, evaluated at snapshots along the MD trajectory. We show that charge transport can be promoted through the coupling to solvent fluctuations, which gate the onsite energies along the DNA wire

Charge transport through bio-molecular wires in a solvent: Bridging molecular dynamics and model Hamiltonian approaches

We present a hybrid method based on a combination of quantum/classical molecular dynamics (MD) simulations and a mod el Hamiltonian approach to describe charge transport through bio-molecular wires with variable lengths in presence o f a solvent. The core of our approach consists in a mapping of the bio-molecular electronic structure, as obtained f rom density-functional based tight-binding calculations of molecular structures along MD trajectories, onto a low di mensional model Hamiltonian including the coupling to a dissipative bosonic environment. The latter encodes fluctuat ion effects arising from the solvent and from the molecular conformational dynamics. We apply this approach to the c ase of pG-pC and pA-pT DNA oligomers as paradigmatic cases and show that the DNA conformational fluctuations are essential in determining and supporting charge transport

Robust signatures in the current-voltage characteristics of DNA molecules oriented between two graphene nanoribbon electrodes

In this work we numerically calculate the electric current through three kinds of DNA sequences (telomeric, \lambda-DNA, and p53-DNA) described by different heuristic models. A bias voltage is applied between two zig-zag edged graphene contacts attached to the DNA segments, while a gate terminal modulates the conductance of the molecule. The calculation of current is performed by integrating the transmission function (calculated using the lattice Green's function) over the range of energies allowed by the chemical potentials. We show that a telomeric DNA sequence, when treated as a quantum wire in the fully coherent low-temperature regime, works as an excellent semiconductor. Clear steps are apparent in the current-voltage curves of telomeric sequences and are present independent of lengths and sequence initialisation at the contacts. The current-voltage curves suggest the existence of stepped structures independent of length and sequencing initialisation at the contacts. We also find that the molecule-electrode coupling can drastically influence the magnitude of the current. The difference between telomeric DNA and other DNA, such as \lambda-DNA and DNA for the tumour suppressor p53, is particularly visible in the length dependence of the current