Motivated by recent experiments [Lee et al. Nature 498, 209 (2013)], we present here a detailed theoretical analysis of the Joule heating in current-carrying single-molecule junctions. By combining Landauer approach for quantum transport with ab initio calculations, show how electrodes molecular junction is determined its electronic structure. In particular, that general heat not equally dissipated both and it depends on bias polarity (or equivalently current direction). These asymmetries...

Abstract Studying the thermoelectric effect in DNA is important for unravelling charge transport mechanisms and developing relevant applications of molecules. Here we report a study single By varying molecular length sequence, tune to either hopping- or tunnelling-dominated regimes. The small insensitive hopping regime. In contrast, large sensitive tunnelling These findings indicate that one may control by its sequence length. We describe experimental results terms models.

Dual-purpose activation: Peptide C-terminal azlactones I undergo stereoselective alkylation with high efficiency by the use of a newly devised chiral tetraaminophosphonium salt as phase-transfer catalyst, and alkylated azlactone products II can be employed directly for peptide ligation (see scheme, LG=leaving group). In this way, wide range quaternary α-amino acid residues incorporated at specific sites strand.

Designing, controlling, and understanding rectification behavior in molecular-scale devices has been a goal of the molecular electronics community for many years. Here we study transport single molecule diode, its nonrectifying, symmetric counterpart at low temperatures, both high biases to help elucidate electron–phonon interactions mechanisms rectifying system. We find that onset current occurs biases, indicating significant change elastic pathway. However, peaks inelastic electron...

We report controlling the formation of single-molecule junctions by means electrochemically reducing two axialdiazonium terminal groups on a molecule, thereby producing direct Au–C covalent bonds in situ between molecule and gold electrodes. yield enhancement molecular junction as electrochemical potential both electrodes approach reduction diazonium groups. Step length analysis shows that is significantly more stable, can be pulled over longer distance than comparable created with amine...

In this paper, we have systematically studied how the replacement of a benzene ring by heterocyclic compound in oligo(phenyleneethynylene) (OPE) derivatives affects conductance molecular wire using scanning tunneling microscope-based break junction technique. We describe for first time OPE with central pyrimidine can efficiently link to gold electrode two pathways presenting different G values. demonstrated that effect is associated presence efficient conductive length: conventional...

Here we present a theoretical study of the thermoelectric transport through [2,2]paracyclophane-based single-molecule junctions. Combining electronic and vibrational structures, obtained from density functional theory (DFT), with nonequilibrium Green's function techniques allows us to treat both phononic properties at first-principles level. For part, include an approximate self-energy correction, based on DFT+$\ensuremath{\Sigma}$ approach. This enables make reliable prediction all linear...

The Madelung energy in the (Y, Ca)(Ba, La) 2 Cu 3 O 6+δ system has been calculated order to find distribution of hole carriers among sites. We regard compoundas a superconductor, when lowest-energy is such that holes enter sites CuO sheets, whereas we it as semiconductor, no sheets. Based on this criterion, phase diagram, where superconducting region separated from semi-conducting by boundary. A good agreement with experimental finding Tokura et al . obtained, account taken ordering exygen...

We studied electron transport of Ru complex multilayer films, whose structure resembles redox-active films known in the literature to have long-range abilities. Hydrogen bond formation terms pH control was used induce spontaneous growth a multilayer. made cross-check between electrochemical measurements and I–V using PEDOT:PSS eliminate risk pinhole contributions mechanism found small β values 0.012–0.021 Å–1. Our layers exhibit but with low conductance. On basis results our...

Large-scale first-principles transport calculations, while essential for device modeling, remain computationally demanding. To overcome this bottle neck, we combine calculations with machine learning-based nonlinear regression. We calculate the electronic conductance through based nonequilibrium Green's function techniques small systems and map properties onto local using descriptors. show that descriptor as input features deep regression allows us to build a robust neural network can...

We have studied nonequilibrium phonon effects on the electric current and energy through atomic molecular bridge junctions in terms of Su-Schrieffer-Heeger model. Due to inelastic coupling between electrons phonons, two currents are closely correlated. The correlation was taken into account our theory where kinetic equations solved not only for but also phonons. offset behavior tunneling spectrum is successfully described by theory. In addition this, it found that a vibronic arises as result...

A screened Hartree-Fock (HF) exchange potential with the dielectric constant was previously reported by Shimazaki and Asai [Chem. Phys. Lett. 466, 91 (2008)], in which inverse of used to represent a fraction HF term. In that report, experimentally obtained value for employed. Herein, we discuss self-consistent technique, can be automatically determined. This technique enables energy band structure determined without using experimental value. The diamond is calculated, procedure give closer...

The screening effect on the Hartree-Fock (HF) exchange term plays a key role in investigation of solid-state materials by first-principles electronic structure calculations. We recently proposed novel screened HF potential, which inverse dielectric constant represents fraction incorporated into potential. demonstrated that this approach can be used to reproduce energy band diamond well [T. Shimazaki and Y. Asai, J. Chem. Phys. 130, 164702 (2009)]. In present paper, we report method is...

A theoretical study of an interfacial phase change memory made a GeTe–Sb₂Te₃ superlattice with W electrodes is presented to identify the high and low resistance states switching mechanism.

A novel microscopic mechanism of bidirectional structural changes is proposed for the photoinduced magnetic phase transition in Co-Fe Prussian blue analogs on basis ab initio quantum chemical cluster calculations. It shown that local potential energies various spin states Co are sensitive to number nearest neighbor Fe vacancies. As a result, forward and backward most readily initiated by excitation different regions photons. This suggests an effective strategy realize reversible transitions...

We have studied adiabatic and nonadiabatic electron--intramolecular-vibration (e-MV) couplings in doped ${\mathrm{C}}_{60}$. shown that e-MV the multiband system bring about an interband pair transfer interaction to give ${\mathit{T}}_{\mathit{c}}$ enhancement. estimated coupling constants of The dimensionless with three lowest ${\mathit{h}}_{\mathit{g}}$ modes are large (0.2--0.4) they dominate be 0.02--0.12. They cannot neglected quantitative arguments. may important even qualitative...

The length-dependent conductance of molecular wires and quantum dot array has been theoretically investigated based on finite size one-dimensional model. It clarified that the dependences length chain have qualitatively different characteristics even for noninteracting electrons as Fermi energy lead is varied relative to spectra atoms. also found magnitude transfer integrals in electrode, those between electrode plays a crucial role conductance. We dependence these cases more physics besides...

We have both experimentally and theoretically studied low voltage rectification phenomena in an asymmetric single diblock molecular junction analyzed its mechanism. First-principles nonequilibrium Green's function (NEGF) theory was applied to electric current calculations. Then we identified a conducting orbital based on the Breit–Wigner formula combined with effective projected state Hamiltonian (MPSH) analysis, where real complex energy terms are renormalized explicitly into standard MPSH...

We have observed and analyzed a universal temperature crossover behavior of electrical conductance in single oligothiophene molecular wire. The between the Arrhenius-type dependence at high temperature-invariant low is found critical wire length 5.6 nm, where we change from exponential to length-invariant behavior. derived scaling function analysis for origin After assuring that fits explanation Keldysh Green's calculation dependence, applied it our experimental results successfully gives...

First-principles modeling shows how resistive switching in oxide heterostructures is improved by inserting an “oxygen scavenger” layer.

An electronic structure theory has been developed for an inelastic electric current of electron-intramolecular vibration coupling origin in terms the Keldysh Green function method and self-consistent Born approximation. Numerical calculations were made benzenedithiol molecule linking two Au(111) electrodes. The successfully reproduce typical features commonly observed tunneling spectroscopy. vibrational excitation energy due to was estimated. is quite important structural stability switching...

Zweimal nützlich: C-terminale Peptidazlactone I werden mithilfe eines neuartigen chiralen Tetraaminophosphoniumsalzes als Phasentransferkatalysator (PTC) hocheffizient stereoselektiv alkyliert, und die alkylierten Azlactonprodukte II können direkt zur Peptidligation eingesetzt (siehe Schema). Auf diese Art lässt sich eine Vielfalt an quartären α-Aminosäureresten gezielt in einen Peptidstrang einfügen. Detailed facts of importance to specialist readers are published as ”Supporting...

Single molecule devices provide a unique system to study the thermoelectric energy conversion at an atomistic level and can valuable information for design of organic materials. Here we present comprehensive transport properties molecular junctions based on C82, Gd@C82, Ce@C82. We combine precise scanning tunneling microscope break-junction measurements thermopower conductance with quantitatively accurate self-energy-corrected first-principles calculations. find that all three fullerene...