Finite-bias electronic transport of molecules in a water solution

Rungger, Ivan; Chen, X.; Schwingenschlögl, Udo; Sanvito, Stefano

doi:10.1103/physrevb.81.235407

Cited by 43 publications

(62 citation statements)

References 44 publications

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“…For instance, the confirmation assumed by DNA double helices is itself determined by the extent to which the molecules are surrounded by water and by the energy associated with hydration. Additionally, as shown recently by Rungger et al, 56 in molecular junctions, solvation by water effectively produces electrostatic gating which can change the average alignment of the molecular energy levels with respect to the leads E F . Finally, around room temperature the thermal motion of water molecules can produce rapidly fluctuating local dipolar fields that, in turn, lead to fluctuations in the energy-level positions of individual molecular orbitals on the DNA.…”

Section: Solvent Effectsmentioning

confidence: 99%

“…This is similar to what found for benzene molecules attached to gold via thiol groups. 56 Furthermore, the HOMO and LUMO energies fluctuate about the mean value with a standard deviation of 0.36 eV and 0.28 eV, respectively. It is worth noting that although the peak of the histogram for the HOMO level in the presence of the solvent is ϳ1.5 eV lower than the HOMO level in vacuum, energies near the right edge of the histogram are relevant for the observed I-V characteristics.…”

Section: Solvent Effectsmentioning

confidence: 99%

“…The strategy adopted for investigating the effects of the solution on the electronic transport is the same reported recently in reference. 56 It consists first in performing classical molecular-dynamics ͑MD͒ simulations in order to describe the average geometrical arrangement of the solvent around the DNA, and then in evaluating the average FIG. 9.…”

Section: Solvent Effectsmentioning

confidence: 99%

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Ab initiostudy of electron transport in dry poly(G)-poly(C)A-DNA strands

et al. 2010

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The bias-dependent transport properties of short poly͑G͒-poly͑C͒ A-DNA strands attached to Au electrodes are investigated with first-principles electronic-transport methods. By using the nonequilibrium Green's function approach combined with self-interaction-corrected density-functional theory, we calculate the fully selfconsistent coherent I-V curve of various double-strand polymeric DNA fragments. We show that electronic wave-function localization, induced either by the native electrical dipole and/or by the electrostatic disorder originating from the first few water solvation layers, drastically suppresses the magnitude of the elastic conductance of A-DNA oligonucleotides. We then argue that electron transport through DNA is the result of sequence-specific short-range tunneling across a few bases combined with general diffusive/inelastic processes.

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Section: Solvent Effectsmentioning

confidence: 99%

Section: Solvent Effectsmentioning

confidence: 99%

Section: Solvent Effectsmentioning

confidence: 99%

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Ab initiostudy of electron transport in dry poly(G)-poly(C)A-DNA strands

et al. 2010

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“…The work functions of EuO and Cu are calculated by using the Hartree electrostatic potential, V H , as the reference potential. 41 We define W Cu as the difference between E F and the vacuum potential V vacuum of a Cu slab, while W EuO is given by the difference between V vacuum and the energy of the valenceband top of a EuO slab, V VB . We calculate W Cu = 3.9 eV, which is somewhat lower than the theoretical values, ranging between 4.5 to 5.3 eV, 42 and the experimental value of about 4.65 eV.…”

Section: Spin Transport Properties Of the Euo Junction At Zero Biasmentioning

confidence: 99%

Electronic transport through EuO spin-filter tunnel junctions

et al. 2012

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Epitaxial spin-filter tunnel junctions based on the ferromagnetic semiconductor europium monoxide (EuO) are investigated by means of density functional theory. In particular, we focus on the spin transport properties of Cu(100)/EuO(100)/Cu(100) junctions. The dependence of the transmission coefficient and the current-voltage curves on the interface spacing and EuO thickness is explained in terms of the EuO density of states and the complex band structure. Furthermore, we also discuss the relation between the spin transport properties and the Cu-EuO interface geometry. The level alignment of the junction is sensitively affected by the interface spacing, since this determines the charge transfer between EuO and the Cu electrodes. Our calculations indicate that EuO epitaxially grown on Cu can act as a perfect spin filter, with a spin polarization of the current close to 100%, and with both the Eu-5d conduction-band and the Eu-4f valence-band states contributing to the coherent transport. For epitaxial EuO on Cu, a symmetry filtering is observed, with the 1 states dominating the transmission. This leads to a transport gap larger than the fundamental EuO band gap. Importantly, the high spin polarization of the current is preserved up to large bias voltages.

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“…Furthermore, additional fluctuations may arise from the electrostatic gate action introduced by the solvent molecules. 5,6 In order to overcome these intrinsic difficulties, it was further suggested to trace the current fluctuations as the ssDNA is translocated across the pore, and to use their statistical distribution in order to unambiguously recognize the electronic signatures of the various nucleobases. [7][8][9] Experimentally, Tsutsui et al showed that it is possible to identify single nucleotides in solution by two-probe tunneling current measurements and a thorough statistical analysis of the time-resolved current.…”

Section: Introductionmentioning

confidence: 99%

First-principles study of high-conductance DNA sequencing with carbon nanotube electrodes

et al. 2012

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Rapid and cost-effective DNA sequencing at the single nucleotide level might be achieved by measuring a transverse electronic current as single-stranded DNA is pulled through a nanometer-sized pore. In order to enhance the electronic coupling between the nucleotides and the electrodes and hence the current signals, we employ a pair of single-walled close-ended (6,6) carbon nanotubes (CNTs) as electrodes. We then investigate the electron transport properties of nucleotides sandwiched between such electrodes by using first-principles quantum transport theory. In particular, we consider the extreme case where the separation between the electrodes is the smallest possible that still allows the DNA translocation. The benzene-like ring at the end cap of the CNT can strongly couple with the nucleobases and therefore it can both reduce conformational fluctuations and significantly improve the conductance. As such, when the electrodes are closely spaced, the nucleobases can pass through only with their base plane parallel to the plane of CNT end caps. The optimal molecular configurations, at which the nucleotides strongly couple to the CNTs, and which yield the largest transmission, are first identified. These correspond approximately to the lowest energy configurations. Then the electronic structures and the electron transport of these optimal configurations are analyzed. The typical tunneling currents are of the order of 50 nA for voltages up to 1 V. At higher bias, where resonant transport through the molecular states is possible, the current is of the order of several μA. Below 1 V, the currents associated to the different nucleotides are consistently distinguishable, with adenine having the largest current, guanine the second largest, cytosine the third and, finally, thymine the smallest. We further calculate the transmission coefficient profiles as the nucleotides are dragged along the DNA translocation path and investigate the effects of configurational variations. Based on these results, we propose a DNA sequencing protocol combining three possible data analysis strategies.

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Finite-bias electronic transport of molecules in a water solution

Cited by 43 publications

References 44 publications

Ab initiostudy of electron transport in dry poly(G)-poly(C)A-DNA strands

Ab initiostudy of electron transport in dry poly(G)-poly(C)A-DNA strands

Electronic transport through EuO spin-filter tunnel junctions

First-principles study of high-conductance DNA sequencing with carbon nanotube electrodes

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