Can molecular projected density of states (PDOS) be systematically used in electronic conductance analysis?

• Tonatiuh Rangel,
• Gian-Marco Rignanese and
• Valerio Olevano

Beilstein J. Nanotechnol. 2015, 6, 1247–1259, doi:10.3762/bjnano.6.128

• ; benzene-dithiol; DFT-Landauer; molecular electronics; nanoelectronics; quantum transport; Introduction According to Moore’s law, in a decade or so, the downscaling of conventional silicon-based electronics will achieve its ultimate nanoscale limit. Molecular electronics, or electronics at the nanoscale

• established frameworks [5][6] like the Kubo–Greenwood [7][8] or the Landauer [9] formalisms, or the non-equilibrium Green’s function theory [10][11][12]. In the last two decades, the combination of these formalisms with density functional theory (DFT) or many-body perturbation (MBPT) theory allowed for the

• establishment of ab initio approaches to quantum transport. The DFT-Landauer framework is one of the most popular. It has proven successful in calculating zero-bias conductances in good agreement with the experiment in some systems such as the hydrogen molecule between platinum wires [13]. In other systems

Enhancing the thermoelectric figure of merit in engineered graphene nanoribbons

• Hatef Sadeghi,
• Sara Sangtarash and
• Colin J. Lambert

Beilstein J. Nanotechnol. 2015, 6, 1176–1182, doi:10.3762/bjnano.6.119

• Hamiltonian of the structure analogously as described in [9], we employed the SIESTA [13] implementation of DFT using the generalized gradient approximation (GGA) of the exchange and correlation functional with the Perdew–Burke–Ernzerhof parameterization (PBE) [14] a double zeta polarized basis set, a real

• -space grid defined with a plane wave cut-off energy of 250 Ry and a maximum force tolerance of 40 meV/Å. From the converged DFT calculation, the underlying mean-field Hamiltonian was combined with the GOLLUM [12] implementation of the non-equilibrium Greens function (NEGF) method. This yields the

Electrical characterization of single molecule and Langmuir–Blodgett monomolecular films of a pyridine-terminated oligo(phenylene-ethynylene) derivative

• Henrry M. Osorio,
• Santiago Martín,
• María Carmen López,
• Santiago Marqués-González,
• Simon J. Higgins,
• Richard J. Nichols,
• Paul J. Low and
• Pilar Cea

Beilstein J. Nanotechnol. 2015, 6, 1145–1157, doi:10.3762/bjnano.6.116

• frontier orbital energies and promotes electron transport by reducing the energy offset between the molecular LUMO and the Fermi level of electrodes [102][103][104]. In particular, DFT-based studies of 1 in single molecule junctions have shown that the total conductance is controlled by eigenchannels

Electronic interaction in composites of a conjugated polymer and carbon nanotubes: first-principles calculation and photophysical approaches

• Florian Massuyeau,
• Jany Wéry,
• Jean-Luc Duvail,
• Serge Lefrant,
• Abu Yaya,
• Chris Ewels and
• Eric Faulques

Beilstein J. Nanotechnol. 2015, 6, 1138–1144, doi:10.3762/bjnano.6.115

• network when nanotubes are semiconducting. Keywords: composite; conjugated polymer; DFT calculations; energy transfer; photoconductivity; single wall carbon nanotubes; time-resolved photoluminescence; Introduction Electroactive conjugated polymers (ECPs) are technologically promising for organic light

• density functional theory (DFT) calculations of coupling effects between the polymer and both species of SWNTs. Combined experimental results and first-principles calculations provide evidence that significant electronic interaction can take place between PPV chains and semiconducting SWNTs while metallic

• performed density functional (DFT) calculations under the local density approximation as implemented in the AIMPRO code [21][22], on a triphenyl PPV section (C22H18) oriented parallel to the axis of a metallic (4,4) and semiconducting (7,0) nanotube chosen due to their similar diameters. PPV is arranged

Charge carrier mobility and electronic properties of Al(Op)₃: impact of excimer formation

• Andrea Magri,
• Pascal Friederich,
• Bernhard Schäfer,
• Valeria Fattori,
• Xiangnan Sun,
• Timo Strunk,
• Velimir Meded,
• Luis E. Hueso,
• Wolfgang Wenzel and
• Mario Ruben

Beilstein J. Nanotechnol. 2015, 6, 1107–1115, doi:10.3762/bjnano.6.112

• , the HOMO/LUMO energies of Alq3 are localized mainly on one ligand [40]. The results for HOMO/LUMO levels of Al(Op)3 calculated with DFT (but on different level of theory) are shown in Figure 8. We calculated the ionic and electronic ground state of the molecule in vacuum and extracted the HOMO and the

• importance. Conclusion We have synthesized and characterized a novel, Al-based, metallo-organic molecule as an alternative to the de facto, industry standard, electron transporting material, Alq3. The initial assumptions based on the extended aromatic structure of Al(Op)3 and confirmed by the theoretical DFT

Electrocatalysis on the nm scale

• R. Jürgen Behm

Beilstein J. Nanotechnol. 2015, 6, 1008–1009, doi:10.3762/bjnano.6.103

• developed to a stage where a reliable description of complex surface structures and surface processes (at the solid–gas interface) is possible based on first-principles electronic structure theory (in particular, (periodic) density functional theory (DFT)), but it is also increasingly developing new

Multiscale modeling of lithium ion batteries: thermal aspects

• Arnulf Latz and
• Jochen Zausch

Beilstein J. Nanotechnol. 2015, 6, 987–1007, doi:10.3762/bjnano.6.102

• properties of electrochemically active materials [3][6]. The combination with statistical methods is important to bridge the gap between zero-temperature DFT simulations in vacuum and the properties of the studied materials at finite temperatures in contact with different phases. Standard DFT simulations

• usually concentrate on individual electronic processes without considering the interplay with the environment or competing electronic processes, which might be statistically and thus macroscopically much more significant [7]. In ab initio thermodynamics, DFT is combined with ideas from statistical

• absolute accuracy of the DFT simulation, which usually contain many simplification and assumptions on the structure of the solution [4][5]. By using cluster expansions [8] it is possible to combine DFT with kinetic Monte Carlo (KMC) simulations to obtain collective diffusion coefficients for lithium ions

Graphene on SiC(0001) inspected by dynamic atomic force microscopy at room temperature

• Mykola Telychko,
• Jan Berger,
• Zsolt Majzik,
• Pavel Jelínek and
• Martin Švec

Beilstein J. Nanotechnol. 2015, 6, 901–906, doi:10.3762/bjnano.6.93

• sample. KPFM parabola was measured by sweeping the bias voltage and measuring the Δf value [24]. In order to estimate the SLG corrugation we carried out large scale total energy density functional theory (DFT) calculations. We used local-orbital FIREBALL code [25][26]. FIREBALL uses an optimized [27

A simple approach to the synthesis of Cu_1.8S dendrites with thiamine hydrochloride as a sulfur source and structure-directing agent

• Xiaoliang Yan,
• Sha Li,
• Yun-xiang Pan,
• Zhi Yang and
• Xuguang Liu

Beilstein J. Nanotechnol. 2015, 6, 881–885, doi:10.3762/bjnano.6.90

• high pressure, the complexes decompose and Cu1.8S nuclei are produced, as described by Equation 1: To give a detailed description of the complex, we performed density functional theory (DFT) calculations with a cluster model. In this cluster model, two Cu atoms were added to C12H17ClN4OS·HCl to

• that the Cu–S bonds exhibit a covalent component. In fact, such an interaction between Cu and S can also be understood from the deformation density, as shown in Figure 3b. The DFT results show that an interaction between Cu and S indeed exists. Figure 4 shows the morphological changes of the Cu1.8S

• the dendritic structure ranges from 100 to 300 nm and its diameter from 30 to 50 nm. The formation process of the Cu1.8S dendrite was explored by TEM observations at different reaction times. The DFT results revealed that interactions between Cu and S indeed exists. It was found that the formation of

Statistics of work and orthogonality catastrophe in discrete level systems: an application to fullerene molecules and ultra-cold trapped Fermi gases

• Antonello Sindona,
• Michele Pisarra,
• Mario Gravina,
• Cristian Vacacela Gomez,
• Pierfrancesco Riccardi,
• Giovanni Falcone and
• Francesco Plastina

Beilstein J. Nanotechnol. 2015, 6, 755–766, doi:10.3762/bjnano.6.78

• to compute the work distribution (Section 1), based on the knowledge of the initial ground state and the low-lying final perturbed states of the systems (Section 2). To treat the fullerene molecule, we use density-functional theory (DFT) and simulate the sudden creation of a core state, by replacing

• DFT approach in which we replace the core electrons of a specific atom in the molecule with an effective core potential (ECP) of the Stevens–Basch–Krauss (SBK) type [40], whose parameters are adjusted to describe neutral and core-ionized atomic carbon [10]. The valence electrons in this reference atom

• -valence basis set denoted 6-311G* [41]. We then perform a spin-restricted DFT calculation [42][43][44], working under the generalized gradient approximation (GGA) for electron exchange and correlation, parameterized by the Perdew–Burke–Ernzerhof (PBE) functional [45][46]. All electron spin pairs from the

Chains of carbon atoms: A vision or a new nanomaterial?

• Florian Banhart

Beilstein J. Nanotechnol. 2015, 6, 559–569, doi:10.3762/bjnano.6.58

• bandgap. Simulations show that a strain of 10% leads to a bandgap of 1.5–3.0 eV, depending on the approximation (DFT, GW) [19][23]. The electrical properties of chains can only be measured by contacts through single atoms. The bonding characteristics at this particular point are of paramount importance

• density functional theory (DFT) occurred, leading to the application of more sophisticated and, accordingly, more computationally intensive techniques of simulation. While DFT gave correct calculations of lattice constants and energies, the bandgaps have been considerably underestimated. Many-body

• chains are energetically lower (more favourable) than extremely thin single-wall carbon nanotubes [5][61]. Indeed, no nanotubes with diameters below 4 Å have ever been observed. It has been shown by DFT calculations that an infinite chain is more favourable than an armchair (3,0) or zigzag (2,2) single

Raman spectroscopy as a tool to investigate the structure and electronic properties of carbon-atom wires

• Alberto Milani,
• Matteo Tommasini,
• Valeria Russo,
• Andrea Li Bassi,
• Andrea Lucotti,
• Franco Cataldo and
• Carlo S. Casari

Beilstein J. Nanotechnol. 2015, 6, 480–491, doi:10.3762/bjnano.6.49

• (computed with DFT) are reported for a selection of differently capped sp chains [40]. In hydrogen-capped chains, the H-terminal forces the formation of a triple bond on the adjacent C–C bond, thus a single bond is formed on the next C–C bond, inducing a polyynic structure. A vinylidene cap (i.e., =CH2

• intensity for an increasing wire length (i.e., number of carbon atoms). In addition, recent theoretical analysis carried out with DFT suggests that for long wires under axial strain along the sp-chain, anharmonicity may also drastically affect the Raman spectra, resulting in an interesting interplay with

• Raman signals than polyynes. DFT calculations have quantitatively shown that for realistic systems of finite length, the strong electron–phonon coupling is responsible for the red-shift of the Raman mode when increasing the length [31][33][35][41]. Furthermore, a first interpretation has been carried

In situ scanning tunneling microscopy study of Ca-modified rutile TiO₂(110) in bulk water

• Giulia Serrano,
• Beatrice Bonanni,
• Tomasz Kosmala,
• Marco Di Giovannantonio,
• Ulrike Diebold,
• Klaus Wandelt and
• Claudio Goletti

Beilstein J. Nanotechnol. 2015, 6, 438–443, doi:10.3762/bjnano.6.44

• ) surface. Recently, density functional theory (DFT) calculations have shown that, among the possible sites originally proposed on the basis of STM investigations [1], bridging oxygen (BO) atoms and in-plane oxygen (IO) atoms represent minima in the potential energy surface, thus providing more stable sites

Nanoparticle shapes by using Wulff constructions and first-principles calculations

• Georgios D. Barmparis,
• Zbigniew Lodziana,
• Nuria Lopez and
• Ioannis N. Remediakis

Beilstein J. Nanotechnol. 2015, 6, 361–368, doi:10.3762/bjnano.6.35

• -principles calculations, is a powerful tool for the analysis and prediction of the shapes of nanoparticles and tailor the properties of shape-inducing species. Keywords: density functional theory (DFT); hydrogen storage; multi-scale simulations; nanoparticles; surface energies; surfactants; Wulff

• of catalyst. Nanoparticles that are relevant to catalysis have diameters of the order of 5 nm and contain of the order of 5000 transition metal atoms. Direct simulation of such systems by using quantum-mechanical techniques is difficult at present. Modern DFT codes that can tackle several thousands

Carrier multiplication in silicon nanocrystals: ab initio results

• Ivan Marri,
• Marco Govoni and
• Stefano Ossicini

Beilstein J. Nanotechnol. 2015, 6, 343–352, doi:10.3762/bjnano.6.33

• CM effects in systems of isolated and interacting Si-NCs. Structural and electronic properties are calculated within the density functional theory (DFT) using the local density approximation, as implemented in the QuantumESPRESSO package [37]. Energy levels are determined by considering a

X-ray photoelectron spectroscopy of graphitic carbon nanomaterials doped with heteroatoms

• Toma Susi,
• Thomas Pichler and
• Paola Ayala

Beilstein J. Nanotechnol. 2015, 6, 177–192, doi:10.3762/bjnano.6.17

• [192]. However, unambiguous direct evidence for the bonding of phosphorus in graphitic carbon nanomaterials has been lacking. Based on DFT simulations, it is expected that P will predominantly bond to three C neighbors, but buckle significantly out of the surface due its larger atomic radius [97][101

SERS and DFT study of copper surfaces coated with corrosion inhibitor

• Maurizio Muniz-Miranda,
• Francesco Muniz-Miranda and
• Stefano Caporali

Beilstein J. Nanotechnol. 2014, 5, 2489–2497, doi:10.3762/bjnano.5.258

• anticorrosive thin film, the SERS spectra were interpreted with the aid of theoretical calculations based on the density functional theory (DFT) approach. Keywords: copper corrosion; DFT; inhibitor film; 1,2,4-triazole; SERS; Introduction Copper has a long history in a variety of industrial uses due to its

• surfaces are interpreted with the aid of density functional theory (DFT) calculations, which were able to provide useful information on the adsorption of different ligands on metal surfaces, including corrosion inhibitors [12][13][14][15]. Combining spectroscopic and theoretical results leads to the

• substrate. Raman spectra and DFT analysis The investigation on the layer of adsorbed ligands is based on the analysis of the SERS spectra, in addition to a computational approach using the DFT method. This study is complicated by the fact that the molecule in question is a heterocyclic ring that can bind to

Spectroscopic mapping and selective electronic tuning of molecular orbitals in phosphorescent organometallic complexes – a new strategy for OLED materials

• Pascal R. Ewen,
• Jan Sanning,
• Tobias Koch,
• Nikos L. Doltsinis,
• Cristian A. Strassert and
• Daniel Wegner

Beilstein J. Nanotechnol. 2014, 5, 2248–2258, doi:10.3762/bjnano.5.234

• (phosphorescent) triplet emitters both in monomeric and aggregated form [31][32]. We identified a number of occupied and unoccupied frontier orbitals. Comparison with density functional theory (DFT) calculations allows the unambiguous assignment of all MOs from the HOMO–2 to the LUMO+2. We found that the

• the local density of states of the sample. Energy-resolved spectral maps (that visualize the spatial distribution of molecular orbitals) were acquired by measuring dI/dV at a fixed bias as a function of lateral position in constant-current mode. For the DFT calculations shown here, Kohn–Sham molecular

• results from DFT calculations of C1 in the gas phase (Figure 3a) and dI/dV maps of the first monolayer of C1 on Au(111). The theoretical results contain the shapes and energies of five molecular orbitals with respect to EF . While only one MO (HOMO–1) is exclusively localized at the Pt atom, all other

UHV deposition and characterization of a mononuclear iron(III) β-diketonate complex on Au(111)

• Irene Cimatti,
• Silviya Ninova,
• Valeria Lanzilotto,
• Luigi Malavolti,
• Luca Rigamonti,
• Brunetto Cortigiani,
• Matteo Mannini,
• Elena Magnano,
• Federica Bondino,
• Federico Totti,
• Andrea Cornia and
• Roberta Sessoli

Beilstein J. Nanotechnol. 2014, 5, 2139–2148, doi:10.3762/bjnano.5.223

• regular domains characterized by a flat morphology and height of ≈0.3 nm. Along with these domains, tetra-lobed features adsorbed on the kinks of the herringbone were also observed. DFT-simulated images of the pristine molecule and its possible decomposition products allowed to assess the partial

• ) in octahedral environment were observed. Keywords: Au(111); β-diketonate complexes; DFT; STM; thin films; UPS; XMCD; XPS; Introduction A renewed interest in mononuclear metal complexes has recently arisen due to the observation that systems of this class can behave as single molecule magnets (SMMs

• . As for the Fe 2p region, the signal is detectable but quite noisy at saturation coverage, and practically negligible at t1. Therefore, no useful information about the Fe oxidation state could be retrieved. STM and DFT characterization Spectroscopic characterization indicates that Fe(dpm)3 adsorbs on

Electronic and electrochemical doping of graphene by surface adsorbates

• Hugo Pinto and
• Alexander Markevich

Beilstein J. Nanotechnol. 2014, 5, 1842–1848, doi:10.3762/bjnano.5.195

• demonstrated for various atomic and molecular adsorbates. Electropositive elements that easily donate their outer shell electrons are expected to be n-type dopants. Indeed, density functional theory (DFT) calculations predicted group I–III metals to be efficient electron donors for graphene [25][26][27][28

• experimental results, DFT calculations have shown that K atoms act as electron donors [25][26][27][28]. Electronic band structure calculations show that adsorption of a K atom on graphene results in the shift of the Fermi level above the Dirac point, indicating the n-type doping of graphene, Figure 3a

• graphene was studied by synchrotron-based high resolution photoemission spectroscopy (PES) [35]. The increase of the graphene work function due to the deposition of F4-TCNQ (Figure 5) suggests that there is an electron transfer from graphene to the molecule. In agreement with PES measurements DFT

Silicon and germanium nanocrystals: properties and characterization

• Ivana Capan,
• Alexandra Carvalho and
• José Coutinho

Beilstein J. Nanotechnol. 2014, 5, 1787–1794, doi:10.3762/bjnano.5.189

• even the smallest particles that were realized experimentally (about 1000 atoms for ca. 3 nm). Such sizes are close to the practical limits of present-day first-principles density functional theory implementations. Various full-DFT implementations by using localized basis sets such as Aimpro [17][44

Quasi-1D physics in metal-organic frameworks: MIL-47(V) from first principles

• Danny E. P. Vanpoucke,
• Jan W. Jaeken,
• Stijn De Baerdemacker,
• Kurt Lejaeghere and
• Veronique Van Speybroeck

Beilstein J. Nanotechnol. 2014, 5, 1738–1748, doi:10.3762/bjnano.5.184

• framework (MOF) is investigated by using ab initio density functional theory (DFT) calculations. Special focus is placed on the relation between the spin configuration and the properties of the MOF. The ground state is found to be antiferromagnetic, with an equilibrium volume of 1554.70 Å3. The transition

• antiferromagnetic transition pressures. Mapping DFT energies onto a simple-spin Hamiltonian shows both the intra- and inter-chain coupling to be antiferromagnetic, with the latter coupling constant being two orders of magnitude smaller than the former, suggesting the MIL-47(V) to present quasi-1D behavior. The

• dispersion along the the direction of the VO6 chains, similar as for other quasi-1D materials. Keywords: band structure; density functional theory (DFT); low-dimensional electronics; metal-organic frameworks (MOFs); MIL-47; Introduction Metal-organic frameworks (MOFs) present a class of materials located

Liquid fuel cells

• Grigorii L. Soloveichik

Beilstein J. Nanotechnol. 2014, 5, 1399–1418, doi:10.3762/bjnano.5.153

Nano-rings with a handle – Synthesis of substituted cycloparaphenylenes

• Anne-Florence Tran-Van and
• Hermann A. Wegner

Beilstein J. Nanotechnol. 2014, 5, 1320–1333, doi:10.3762/bjnano.5.145

• ring strain and led to a complex mixture of partially dehydrogenated and chlorinated products. A clear evidence for the formation of [3]CHBC was not obtained. DFT calculations showed that the molecule is C3-symmetric with a twisted CPP core and a diameter of 12.2 Å in the gas phase. In the calculated

• and coworkers also reported the synthesis of a [4]cyclo-2,7-pyrenylene ([4]CPY) by using their method with a square-like tetra-Pt-complex [53]. DFT-calculations as well as electrochemical analysis revealed a strong resemblance with [8]CPP. During the evolution of larger π-extended nanobelts, Itami

• host–guest chemistry. In the solid state, the trans structure was calculated to be lower in energy than the cis isomer. However, the dynamic change from trans to cis conformation was studied by DFT calculation and the energy barrier was found to be 13 kcal/mol and 20 kcal/mol for the reverse. The path

Magnesium batteries: Current state of the art, issues and future perspectives

• Rana Mohtadi and
• Fuminori Mizuno

Beilstein J. Nanotechnol. 2014, 5, 1291–1311, doi:10.3762/bjnano.5.143

• study of borohydride-based solid state electrolytes was reported by Higashi et al. [37]. Guided by their first-principles calculations based on density functional theory (DFT), they experimentally investigated the conduction of magnesium ions in both Mg(BH4)2 and Mg(BH4)(NH2). The selection of these