2,402 research outputs found
DNA double helices for single molecule electronics
The combination of self-assembly and electronic properties as well as its
true nanoscale dimensions make DNA a promising candidate for a building block
of single molecule electronics. We argue that the intrinsic double helix
conformation of the DNA strands provides a possibility to drive the electric
current through the DNA by the perpendicular electric (gating) field. The
transistor effect in the poly(G)-poly(C) synthetic DNA is demonstrated within a
simple model approach. We put forward experimental setups to observe the
predicted effect and discuss possible device applications of DNA. In
particular, we propose a design of the single molecule analog of the Esaki
diode.Comment: 4 pages, 4 figur
The effects of de-energizing ties in organizations and how to manage them
PublishedThis is the author accepted manuscript. The final version is available from Elsevier via the DOI in this record.n/
Destructive de-energizing relationships: How thriving buffers their effect on performance.
PublishedThis is the author accepted manuscript. The final version is available from American Psychological Association via the DOI in this record.In this paper, we establish the relationship between de-energizing relationships and individual performance in organizations. To date, the emphasis in social network research has largely been on positive dimensions of relationships despite literature from social psychology revealing the prevalence and detrimental impact of de-energizing relationships. In 2 field studies, we show that de-energizing relationships in organizations are associated with decreased performance. In Study 1, we investigate how de-energizing relationships are related to lower performance using data from 161 people in the information technology (IT) department of an engineering firm. In Study 2, in a sample of 439 management consultants, we consider whether the effects of de-energizing relationships on performance may be moderated by the extent to which an individual has the psychological resource of thriving at work. We find that individuals who are thriving at work are less susceptible to the effects of de-energizing relationships on job performance. We close by discussing implications of this research
Self-assembled guanine ribbons as wide-bandgap semiconductors
We present a first principle study about the stability and the electronic
properties of a new biomolecular solid-state material, obtained by the
self-assembling of guanine (G) molecules. We consider hydrogen-bonded planar
ribbons in isolated and stacked configurations. These aggregates present
electronic properties similar to inorganic wide-bandgap semiconductors. The
formation of Bloch-type orbitals is observed along the stacking direction,
while it is negligible in the ribbon plane. Global band-like conduction may be
affected by a dipole-field which spontaneously arises along the ribbon axis.
Our results indicate that G-ribbon assemblies are promising materials for
biomolecular nanodevices, consistently with recent experimental results.Comment: 7 pages, 3 figures, to be published in Physica
Classical properties of low-dimensional conductors: Giant capacitance and non-Ohmic potential drop
Electrical field arising around an inhomogeneous conductor when an electrical
current passes through it is not screened, as distinct from 3D conductors, in
low-dimensional conductors. As a result, the electrical field depends on the
global distribution of the conductivity sigma(x) rather than on the local value
of it, inhomogeneities of sigma(x) produce giant capacitances C(omega) that
show frequency dependence at relatively low omega, and electrical fields
develop in vast regions around the inhomogeneities of sigma(x). A theory of
these phenomena is presented for 2D conductors.Comment: 5 pages, two-column REVTeX, to be published in Physical Review
Letter
Spin effects in single-electron tunneling in magnetic junctions
Spin dependent single electron tunneling in ferromagnetic double junctions is
analysed theoretically in the limit of sequential tunneling. The influence of
discrete energy spectrum of the central electrode (island)on the spin
accumulation, spin fluctuations and tunnel magnetoresistance is analysed
numerically in the case of a nonmagnetic island. It is shown that spin
fluctuations are significant in magnetic as well as in nonmagnetic junctions.Comment: 14 pages, 3 eps-figures include
Quantum transport through a DNA wire in a dissipative environment
Electronic transport through DNA wires in the presence of a strong
dissipative environment is investigated. We show that new bath-induced
electronic states are formed within the bandgap. These states show up in the
linear conductance spectrum as a temperature dependent background and lead to a
crossover from tunneling to thermal activated behavior with increasing
temperature. Depending on the strength of the electron-bath coupling, the
conductance at the Fermi level can show a weak exponential or even an algebraic
length dependence. Our results suggest a new environmental-induced transport
mechanism. This might be relevant for the understanding of molecular conduction
experiments in liquid solution, like those recently performed on poly(GC)
oligomers in a water buffer (B. Xu et al., Nano Lett 4, 1105 (2004)).Comment: 5 pages, 3 figure
Critical behavior of cascading failures in overloaded networks
In recent years, research on spatial networks has become of widespread
interest, with the focus on analyzing critical phenomena that can dramatically
affect real systems via cascading failures and abrupt collapses. Here, we study
the breakdown of a spatial network having a characteristic link-length due to
overloads and the cascading failures that are triggered by failures of a
fraction of links. While such breakdowns have been studied extensively, the
critical exponents and the universality class of this phase transition have not
been found. Here, we show indications that this transition has features and
critical exponents which are the same as those of interdependent network
systems, suggesting that both systems are in the same universality class. We
find different abrupt transitions at the steady state, for different spatial
embedding strength. For the weakly embedded systems (i.e., link-lengths of the
order of the system size) we observe a mixed-order transition where the order
parameter collapses with time in a long plateau shape. On the other hand, in
strongly embedded systems (relatively short links), we find a pure first order
transition which involves nucleation and growth of damage. System behavior in
both limits is analogous to that observed in interdependent networks.Comment: 7 pages, 6 figure
Electronic transport in DNA
We study the electronic properties of DNA by way of a tight-binding model applied to four particular DNA sequences. The charge transfer properties are presented in terms of localization lengths (crudely speaking, the length over
which electrons travel). Various types of disorder, including random potentials, are employed to account for different real environments. We have performed calculations on poly(dG)-poly(dC), telomeric-DNA, random-ATGC DNA, and l-DNA. We find that random and l-DNA have localization lengths allowing for electron motion among a few dozen basepairs only. A novel enhancement of localization lengths is observed at particular energies for an increasing binary backbone disorder. We comment on the possible biological relevance of sequence-dependent charge transfer in DNA
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