Electronic and transport properties of kinked graphene

• Jesper Toft Rasmussen,
• Tue Gunst,
• Peter Bøggild,
• Antti-Pekka Jauho and
• Mads Brandbyge

Beilstein J. Nanotechnol. 2013, 4, 103–110, doi:10.3762/bjnano.4.12

• atomic and electronic structures we subsequently use the TranSIESTA [31] method to calculate the electronic conductance per unit-cell width transverse to the bend. To this end we attach semi-infinite flat graphene electrodes to each side of the selected kinks, i.e., replace sections S1 and S2 in Figure

•  1b by semi-infinite electrodes in order to calculate the transmission through the single kink separating S1 and S2. In the conductance calculations we employ a dense transverse k-point grid of 400 points. Results and Discussion Adsorption barrier Adsorption of hydrogen on graphene involves a reaction

Nanostructure-directed chemical sensing: The IHSAB principle and the dynamics of acid/base-interface interaction

• James L. Gole and
• William Laminack

Beilstein J. Nanotechnol. 2013, 4, 20–31, doi:10.3762/bjnano.4.3

• electrons, decreases the conductometric resistance and increases conductance. The removal of electrons, as would occur with an acidic analyte, decreases the majority charge carrier concentration and the conductance and increases resistance. The opposite behavior will be observed for a p-type semiconductor

• the nanostructure deposited to the PS surface. TiO2, as a strong acid, enhances the capture of electrons, transferring these electrons to increase conductance (decrease resistance) relative to the undecorated interface. The more basic oxinitride does not facilitate electron transduction as efficiently

• and the sensor response corresponds to a conductance decrease relative to the untreated interface. Note also that the in situ nitridation of TiO2 shifts the nature of this metal oxide nanostructure toward the soft acid side of Figure 2, closer to ammonia. The IHSAB principle dictates [3][6][7][8][24

Sub-10 nm colloidal lithography for circuit-integrated spin-photo-electronic devices

• Adrian Iovan,
• Marco Fischer,
• Roberto Lo Conte and
• Vladislav Korenivski

Beilstein J. Nanotechnol. 2012, 3, 884–892, doi:10.3762/bjnano.3.98

• -type changes in the current–voltage characteristics of our fully enclosed optical resonator. Such threshold-type excitations, of giant magnitude, are indeed observed in the device resistance (conductance changes of a factor of 2), as shown in Figure 5c. This demonstration opens the way to explore a new

Pure hydrogen low-temperature plasma exposure of HOPG and graphene: Graphane formation?

• Baran Eren,
• Dorothée Hug,
• Laurent Marot,
• Rémy Pawlak,
• Marcin Kisiel,
• Roland Steiner,
• Dominik M. Zumbühl and
• Ernst Meyer

Beilstein J. Nanotechnol. 2012, 3, 852–859, doi:10.3762/bjnano.3.96

• probe microscopy were employed for characterization. However, due to the insufficient electrical conductance, it was not possible to use photoelectron spectroscopy and scanning tunneling microscopy techniques for graphene on SiO2. In contrast to plasma treatments in previous works [5][21], mixing of a

Current–voltage characteristics of single-molecule diarylethene junctions measured with adjustable gold electrodes in solution

• Bernd M. Briechle,
• Youngsang Kim,
• Philipp Ehrenreich,
• Artur Erbe,
• Dmytro Sysoiev,
• Thomas Huhn,
• Ulrich Groth and
• Elke Scheer

Beilstein J. Nanotechnol. 2012, 3, 798–808, doi:10.3762/bjnano.3.89

• , Germany Chemistry Department, University of Konstanz, D-78457 Konstanz, Germany 10.3762/bjnano.3.89 Abstract We report on an experimental analysis of the charge transport through sulfur-free photochromic molecular junctions. The conductance of individual molecules contacted with gold electrodes and the

• end-groups designed for providing the mechanical and electrical contact to the gold electrodes. We perform a detailed analysis of the transport properties of TSC in its open and closed states. We find rather broad distributions of conductance values in both states. The analysis, based on the

• switched open or close by irradiation with photons of two distinct wavelengths. Upon this ring-opening/ring-closure reaction the conjugation of the electronic π-system and therefore the conductance is supposed to be strongly affected as well. This ring-opening/ring-closure reaction is accompanied by only a

The memory effect of nanoscale memristors investigated by conducting scanning probe microscopy methods

• César Moreno,
• Carmen Munuera,
• Xavier Obradors and
• Carmen Ocal

Beilstein J. Nanotechnol. 2012, 3, 722–730, doi:10.3762/bjnano.3.82

• is set to the reading area. The tip is biased at Vrd, and topography and current images are simultaneously acquired to characterize the conductance state of the surface. The scan range is reduced to the writing area. The Vtip is set to a given positive value, and topography and current images are

• (Stanford Systems) was used to gain access to a wide range of compliance currents (1 pA to 1 mA). Resistance-switching sequence: Writing and reading of local conductance modifications made on the LSMO surface. The transition between low-resistive (LR) and high-resistive (HR) states is performed by writing

Revealing thermal effects in the electronic transport through irradiated atomic metal point contacts

• Bastian Kopp,
• Zhiwei Yi,
• Daniel Benner,
• Fang-Qing Xie,
• Christian Obermair,
• Thomas Schimmel,
• Johannes Boneberg,
• Paul Leiderer and
• Elke Scheer

Beilstein J. Nanotechnol. 2012, 3, 703–711, doi:10.3762/bjnano.3.80

• nanoscale is one of the central topics in nanoscience. As the size of a contact between two leads is reduced to atomic dimensions, quantum phenomena become relevant in metallic point contacts [1][2][3][4], and it has even become possible to determine the conductance of individual molecules attached between

• two metallic tips both theoretically [4][5][6][7] and experimentally [4][8][9][10][11]. Furthermore the influence of the environment on the conductance of single-molecule junctions [12] has been revealed. In a next step towards molecular electronics, one would like to see such molecules exhibiting

• , in which the influence of light on the conductance behaviour of nanocontacts has been studied, and various mechanisms for such an influence have been suggested [14][15]. In complementary experimental studies it was shown that the conductance of electrical point contacts in a range of one to several

Influence of the diameter of single-walled carbon nanotube bundles on the optoelectronic performance of dry-deposited thin films

• Kimmo Mustonen,
• Toma Susi,
• Antti Kaskela,
• Patrik Laiho,
• Ying Tian,
• Albert G. Nasibulin and
• Esko I. Kauppinen

Beilstein J. Nanotechnol. 2012, 3, 692–702, doi:10.3762/bjnano.3.79

• ]. Since the network resistance scales linearly with the number of contacts, conductance thus scales linearly with the average bundle length. The absorbance (A) and conductance (σDC) can be linked by the so-called figure of merit K [6] where Rs is the sheet resistance and T(λ) (later simply T) the

• than the intratube (or intrabundle) resistance, RI, that is, RJ >> RI. Thus, the conductance of a film (σDC) is expected to depend on the geometric parameters, both because shorter bundles will result in more high-resistance junctions per unit length, and possibly because the bundle geometry alters the

• small. At the edge of the threshold, the conductivity of the network rapidly collapses. Provided Lbundle strictly dictates the geometric scaling of conductance and dbundle the geometric scaling of absorbance, the normalized values should lie on a vertical line, KNORM = constant. Indeed, besides the

Zeolites as nanoporous, gas-sensitive materials for in situ monitoring of DeNO_x-SCR

• Thomas Simons and
• Ulrich Simon

Beilstein J. Nanotechnol. 2012, 3, 667–673, doi:10.3762/bjnano.3.76

• ′(νres) was subsequently determined and plotted in the form of an Arrhenius diagram (Figure 2). In this expression C0 is the geometric capacitance of the empty IDE. The relationship between the imaginary part of the modulus M″ and the conductance G is shown in Equation 2. For the Fe-loaded sample, the

• conductivity was too low to gain clear modulus plots in the temperature range of 110–150 °C. Thus, we used the spectral plot of the phase angle φ (Equation 3) to determine the resonance frequency νres in this temperature region. The relationship between the phase angle φ and the conductance G is shown in

Focused electron beam induced deposition: A perspective

• Michael Huth,
• Fabrizio Porrati,
• Christian Schwalb,
• Marcel Winhold,
• Roland Sachser,
• Maja Dukic,
• Jonathan Adams and
• Georg Fantner

Beilstein J. Nanotechnol. 2012, 3, 597–619, doi:10.3762/bjnano.3.70

• (VRH) conductance mechanism in the presence of electronic correlation effects [12], namely For all other samples either a VRH behavior in three dimensions (3-D) according to Mott (a = 1/4) [32] or some intermediate behavior is apparent. The observed correlated VRH behavior observed for the samples with

• the Hall voltage are shown in Figure 10 for sample B (Figure 10a and Figure 10c) and B' (Figure 10b and Figure 10d). The as-grown sample exhibits a roughly linear temperature dependence of the conductivity down to about 12 K, which is followed by a quite sudden drop to a very small conductance level

• conductance below 12 K, a glassy transition from a superparamagnetic state to a super-spin-glass [47] state may be assumed. However, further work on the low-temperature magnetic state of these deposits is needed before a definite statement can be made. More importantly, the conductivity of the postgrowth

Strong spin-filtering and spin-valve effects in a molecular V–C₆₀–V contact

• Mohammad Koleini and
• Mads Brandbyge

Beilstein J. Nanotechnol. 2012, 3, 589–596, doi:10.3762/bjnano.3.69

• mainly majority-spin electrons to pass (>95%). Moreover, we find a significant change in the conductance between parallel and anti-parallel spin polarizations in the junction (86%) which suggests that STM experiments should be able to characterize the magnetism and spin coupling for these systems

• in a vanishing transmission. The rotational symmetric m = 0 channels appear as resonances in the channel transmissions above EF and thus play a minor role. In typical STM experiments the conductance is probed from the tunnel-regime to contact. We have performed transport calculations as the tip is

• approaching the surface adatom until the tip–molecule distance (d shown in Figure 1) approximately reaches the equilibrium distance discussed above. In Figure 4 we display the conductance along with the corresponding TSP as a function of the tip distance. As can be seen, there is a trend of an increasing

A facile approach to nanoarchitectured three-dimensional graphene-based Li–Mn–O composite as high-power cathodes for Li-ion batteries

• Wenyu Zhang,
• Yi Zeng,
• Chen Xu,
• Ni Xiao,
• Yiben Gao,
• Lain-Jong Li,
• Xiaodong Chen,
• Huey Hoon Hng and
• Qingyu Yan

Beilstein J. Nanotechnol. 2012, 3, 513–523, doi:10.3762/bjnano.3.59

• /G electrodes, and thereby indicates a poorer charge-transfer conductance [29]. The diameters of the semicircles are also smaller for samples with lower ILMO:G values, which suggests that the graphene sheets serve as the 3D conducting scaffold to improve the Li storage performance of the hybrid

P-wave Cooper pair splitting

• Henning Soller and
• Andreas Komnik

Beilstein J. Nanotechnol. 2012, 3, 493–500, doi:10.3762/bjnano.3.56

• function of charge transfer. As a first step, we discuss characteristics of the conductance for crossed Andreev reflection in superconductor–ferromagnet beam splitters with s-wave and p-wave superconductors and no spin-active scattering. In a second step, we consider spin-active scattering and show how to

• realize p-wave splitting using only an s-wave superconductor, through the process of spin-flipped crossed Andreev reflection. We present results for the conductance and cross correlations. Conclusion: Spin-activity of interfaces in Cooper pair splitters allows for new features in ordinary s-wave Cooper

• ]. Results and Discussion Superconductor–ferromagnet beam splitters Splitting of spin-polarized p-wave Cooper pairs can easily be identified in the conductance. From the result in [27] we find the generalization of Beenakker’s formula [34] for the zero-bias conductance of a beam splitter realized by a

Functionalised zinc oxide nanowire gas sensors: Enhanced NO₂ gas sensor response by chemical modification of nanowire surfaces

• Eric R. Waclawik,
• Jin Chang,
• Andrea Ponzoni,
• Isabella Concina,
• Dario Zappa,
• Elisabetta Comini,
• Nunzio Motta,
• Guido Faglia and
• Giorgio Sberveglieri

Beilstein J. Nanotechnol. 2012, 3, 368–377, doi:10.3762/bjnano.3.43

• thiol (confirmed by FTIR) raised the conductivity of each individual sensor above the measurement range of our instrument (which corresponds to a minimum conductance value of Gmax = 10 mS). We conclude from this that chemisorption of the thiol significantly increased the density of electrons present in

• inset). Looking at the overall results obtained with all the sensor replicas, as shown in Table 1, the more effective baseline conductance increase obtained after coating with THMA-ZnO nanoparticles compared to the THMA-coating, can be explained in terms of a preferential charge-carrier injection from

• electrical resistance and conductance of the sample. Sensor response was measured at 190 °C operating temperature. We established through the TG measurements of functionalised ZnO samples, that the degradation of the organic capping layer of the nanowires and nanoparticles at this operating temperature was

Simultaneous current, force and dissipation measurements on the Si(111) 7×7 surface with an optimized qPlus AFM/STM technique

• Zsolt Majzik,
• Martin Setvín,
• Andreas Bettac,
• Albrecht Feltz,
• Vladimír Cháb and
• Pavel Jelínek

Beilstein J. Nanotechnol. 2012, 3, 249–259, doi:10.3762/bjnano.3.28

• . reported a so called “phantom force” phenomenon [30], in which an additional force arises due to a limited electron transport of injected charge in samples with low conductance. However, not much is known currently about its impact on the dissipation signal. In this section we analyze the effect of the

Current-induced forces in mesoscopic systems: A scattering-matrix approach

• Niels Bode,
• Silvia Viola Kusminskiy,
• Reinhold Egger and
• Felix von Oppen

Beilstein J. Nanotechnol. 2012, 3, 144–162, doi:10.3762/bjnano.3.15

• . [4] and leads to their well-known formula for the conductance of multiterminal mesoscopic conductors. For time-dependent phenomena, scattering-matrix expressions have been obtained for quantum pumping [5][6], a process by which a direct current is generated through temporal variations of relevant

Surface functionalization of aluminosilicate nanotubes with organic molecules

• Wei Ma,
• Weng On Yah,
• Hideyuki Otsuka and
• Atsushi Takahara

Beilstein J. Nanotechnol. 2012, 3, 82–100, doi:10.3762/bjnano.3.10

• applied bias voltage in the range from −30 to 30 V, are shown in Figure 19. The averaged electrical conductance calculated from the forward bias region of the pure imogolite I–V curve is 5.9 µS. It was speculated that the current flow was due to charge hopping on the hydrated imogolite surface. Oh et al

• net change of surface charge. The electrical conductance of HT3OP/imogolite was improved to 60.8 µS, which is one order of magnitude greater than that of pure imogolite. It was observed that HT3OP/imogolite shows non-ohmic characteristics in the I–V curve, which signifies a disordered packing of HT3OP

• , the electrical conductance of HT3P/imogolite calculated from the forward bias region is 4.5 µS, which is lower than that before HT3P doping. Here, HT3P acts like an electron donor when interacting with imogolite. The p-type conductivity of imogolite is reduced when the HT3P thiophene ring transfers

Transmission eigenvalue distributions in highly conductive molecular junctions

• Justin P. Bergfield,
• Joshua D. Barr and
• Charles A. Stafford

Beilstein J. Nanotechnol. 2012, 3, 40–51, doi:10.3762/bjnano.3.5

• experimental conductance histogram [4]. In the calculation of the matrix elements, we use the effective Bohr radius of a π-orbital a* = a0/Z, where a0 ≈ 0.53 Å is the Bohr radius and Z = 3.22 is the effective hydrogenic charge associated with the π-orbital quadrupole moment −0.65 eÅ2, determined by π-EFT. For

• , the conductance histogram over the ensemble of junctions can be computed, and is shown in Figure 6. The constant prefactor C appearing in the tunneling matrix elements [25] in Equation 24 was determined by fitting the peak of the calculated conductance distribution to that of the experimental

• conductance histogram [4]. Note that the width of the calculated conductance peak is also comparable to that of the experimental peak [4]. Results and Discussion The transmission eigenvalue distributions for ensembles of 1.74 × 105 Pt–benzene–Pt junctions calculated by using the full many-body spectrum and in

X-ray spectroscopy characterization of self-assembled monolayers of nitrile-substituted oligo(phenylene ethynylene)s with variable chain length

• Hicham Hamoudi,
• Ping Kao,
• Alexei Nefedov,
• David L. Allara and
• Michael Zharnikov

Beilstein J. Nanotechnol. 2012, 3, 12–24, doi:10.3762/bjnano.3.2

• . Another essential element of the experiments is the variation of the length of the molecular wire [3][4][12][14][18][20], which allows further insight into the mechanism of conductance, described as nonresonant superexchange tunneling in most cases [21], and gives the capability to determine essential

When “small” terms matter: Coupled interference features in the transport properties of cross-conjugated molecules

• Gemma C. Solomon,
• Justin P. Bergfield,
• Charles A. Stafford and
• Mark A. Ratner

Beilstein J. Nanotechnol. 2011, 2, 862–871, doi:10.3762/bjnano.2.95

• ][6][7][8][9][10][11][12][13], although the total conductance is nonzero, as underlying σ-system transport dominates in the vicinity of the node [8][9]. Through careful design, interference effects can be perturbed by chemical modification or an external electric field [6][14], presenting myriad

• order of a few electronvolts; however, even a small shift of ~0.5 eV away from the Fermi energy can mean that an interference feature has no bearing on the low-bias conductance. Here we show that “small” terms in the Hamiltonian can shift and change interference features considerably, and these types of

• transport. From a theoretical standpoint, these systems offer an excellent opportunity to discriminate between theoretical methods. When methods differ, the predicted conductance can change by orders of magnitude and this clearly provides a useful tool with which to probe the significance of the various

Current-induced dynamics in carbon atomic contacts

• Jing-Tao Lü,
• Tue Gunst,
• Per Hedegård and
• Mads Brandbyge

Beilstein J. Nanotechnol. 2011, 2, 814–823, doi:10.3762/bjnano.2.90

• , recently it was pointed out [5][6][7][8] that other current-induced forces can play a role. For instance, in the case of molecular contacts with conductance on the order of G0 = 2e2/h = 1/12.9 kΩ (e being the electron charge and h Planck’s constant), and under “high” bias voltage (~1 V), the current

Effect of the environment on the electrical conductance of the single benzene-1,4-diamine molecule junction

• Shigeto Nakashima,
• Yuuta Takahashi and
• Manabu Kiguchi

Beilstein J. Nanotechnol. 2011, 2, 755–759, doi:10.3762/bjnano.2.83

• conductance of a single benzene-1,4-diamine (BDA) molecule bridging Au electrodes, using the scanning tunneling microscope (STM). The conductance of the single BDA molecule junction decreased upon a change in the environment from tetraglyme, to mesitylene, to water, and finally to N2 gas, while the spread in

• the conductance value increased. The order of the conductance values of the single BDA molecule junction was explained by the strength of the interaction between the solvent molecules and the Au electrodes. The order of the spread in the conductance values was explained by the diversity in the

• coverage of the BDA molecule at metal electrodes and atomic and molecular motion of the single-molecule junction. Keywords: benzene-1,4-diamine; electric conductance; single-molecule junction; solvent; Introduction The electron transport properties through a single molecule bridging metal electrodes

Towards quantitative accuracy in first-principles transport calculations: The GW method applied to alkane/gold junctions

• Mikkel Strange and
• Kristian S. Thygesen

Beilstein J. Nanotechnol. 2011, 2, 746–754, doi:10.3762/bjnano.2.82

• Mikkel Strange Kristian S. Thygesen Center for Atomic-scale Materials Design, Department of Physics Technical University of Denmark, DK - 2800 Kgs. Lyngby, Denmark 10.3762/bjnano.2.82 Abstract The calculation of the electronic conductance of nanoscale junctions from first principles is a long

• -standing problem in the field of charge transport. Here we demonstrate excellent agreement with experiments for the transport properties of the gold/alkanediamine benchmark system when electron–electron interactions are described by the many-body GW approximation. The conductance follows an exponential

• length dependence: Gn = Gc exp(−βn). The main difference from standard density functional theory (DFT) calculations is a significant reduction of the contact conductance, Gc, due to an improved alignment of the molecular energy levels with the metal Fermi energy. The molecular orbitals involved in the

Lifetime analysis of individual-atom contacts and crossover to geometric-shell structures in unstrained silver nanowires

• Christian Obermair,
• Holger Kuhn and
• Thomas Schimmel

Beilstein J. Nanotechnol. 2011, 2, 740–745, doi:10.3762/bjnano.2.81

• fabrication of mechanically unstrained structures, which is a requirement for determining the individual atomic configuration by means of a detailed lifetime analysis of their conductance. Within the geometric-shell model, the sequence of conductance maxima is explained quantitatively based on the crystal

• way, switching between a quantized conducting “on-state” and an insulating “off-state” is performed. Even multilevel quantum switches on the atomic scale were demonstrated very recently [6]. The possibility of training special atomic configurations related to certain conductance values, and the high

• stability of the chosen conductance levels, are unique features of the electrochemical method [4][5][6][7][8][9][10]. Compared with mechanical setups, and separate from purely electrochemical methods, electromigration is another promising method to produce bistable contact configurations between integer

Interaction of spin and vibrations in transport through single-molecule magnets

• Falk May,
• Maarten R. Wegewijs and
• Walter Hofstetter

Beilstein J. Nanotechnol. 2011, 2, 693–698, doi:10.3762/bjnano.2.75

• conductance. This Kondo effect is dynamically generated by vibrational fluctuations which distort the SMM, and thereby allow the spin to fluctuate. More generally, a higher QST-Kondo temperature may result from spin-vibration coupling, which is relevant for experimental investigation of low temperature

• zero-temperature differential conductance [19], as a function of the bias voltage V, were obtained from the SMM spectral function A(ω). Here ΓL,R is the tunnel coupling of the SMM to the left and right electrode. We calculated using the numerical renormalization group (NRG) from the equilibrium

• spectral function within the T-matrix approach [20]. In linear response to V, A(0) provides a numerically exact result for the linear conductance through G(0). Moreover, for strong asymmetric coupling of the SMM to the electrodes, the nonequilibrium corrections to the spectral function A(ω) are suppressed