The electronic spin filtering capability of a single chiral helical peptide is measured. A ferromagnetic electrode source employed to inject spin-polarized electrons in an asymmetric single-molecule junction bridging α-helical sequence known chirality. conductance comparison between both isomers allows the direct determination polarization power individual molecule.

In this paper we report on a systematic investigation, in the $5\phantom{\rule{0.3em}{0ex}}\text{to}\phantom{\rule{0.3em}{0ex}}300\phantom{\rule{0.3em}{0ex}}\mathrm{K}$ temperature regime, of electronic, magnetotransport, thermoelectric, thermal, and elastic properties four ${M}_{2}\mathrm{Al}\mathrm{C}$ phases: ${\mathrm{Ti}}_{2}\mathrm{Al}\mathrm{C}$, ${\mathrm{V}}_{2}\mathrm{Al}\mathrm{C}$, ${\mathrm{Cr}}_{2}\mathrm{Al}\mathrm{C}$, ${\mathrm{Nb}}_{2}\mathrm{Al}\mathrm{C}$. The electrical...

Abstract Extensive evidence has shown that long-range charge transport can occur along double helical DNA, but active control (switching) of single-DNA conductance with an external field not yet been demonstrated. Here we demonstrate switching in DNA by replacing a base redox group. By applying electrochemical (EC) gate voltage to the molecule, switch group between oxidized and reduced states, leading reversible two discrete levels. We further show monitoring individual allows study reaction...

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.

An exponential decrease of molecular conductance with length has been observed in most systems reported to date, and taken as a signature non-resonant tunneling the conduction mechanism. Surprisingly, iodide-terminated oligothiophene molecules presented herein does not follow simple dependence. The lack temperature dependence indicates that still dominates mechanism molecules. Transition voltage spectroscopy shows barrier decreases length, but is insufficient explain non-exponential X-ray...

The dopamine-TiO2 system shows a specific spectroscopic response, surface enhanced Raman scattering (SERS), whose mechanism is not fully understood. In this study, the goal to reveal key role of molecule–nanoparticle interface in electronic structure by means ab initio modeling. dopamine adsorption energy on anatase surfaces computed and related changes structure. Two features are observed: appearance state material band gap, charge transfer between molecule upon excitation. analysis...

Zinc phosphorus trisulfide (ZnPS$_3$), a promising material for photocatalysis and energy storage, is shown in this study to exhibit remarkable stability under extreme conditions. We explore its optical structural properties high pressure cryogenic temperatures using photoluminescence (PL) spectroscopy, Raman scattering, density functional theory (DFT). Our results identify pressure-induced phase transition starting at 6.75 GPa stabilizing by 12.5 GPa, after which ZnPS$_3$ demonstrates...

In this paper we report on the electronic, elastic, and thermal properties of ${\mathrm{Ti}}_{3}{\mathrm{Si}}_{1\ensuremath{-}x}{\mathrm{Ge}}_{x}{\mathrm{C}}_{2}$. The conductivities, Hall coefficients, magnetoresistances are analyzed within a two-band framework assuming temperature-independent charge carrier concentrations. framework, ${\mathrm{Ti}}_{3}{\mathrm{Si}}_{1\ensuremath{-}x}{\mathrm{Ge}}_{x}{\mathrm{C}}_{2}$ is shown to be compensated material, i.e., concentration electrons nearly...

Studying the structural and charge transport properties in DNA is important for unraveling molecular scale processes developing device applications of molecules. Here we study effect mechanical stretching-induced changes on single The follows hopping mechanism molecules with lengths varying from 6 to 26 base pairs, but conductance highly sensitive stretching, showing an abrupt decrease at surprisingly short stretching distances weak dependence length. We attribute this force-induced breaking...

Abstract Piezoresistivity is a fundamental property of materials that has found many device applications. Here we report piezoresistivity in double helical DNA molecules. By studying the dependence molecular conductance and single molecules with different sequences lengths, performing orbital calculations, show caused by force-induced changes π–π electronic coupling between neighbouring bases, activation energy hole hopping. We describe results terms thermal activated hopping model together...

We present a sequential molecular dynamics/quantum mechanics (MD/QM) study and steady-state spectroscopy measurements of the nanostar dendrimer (a phenylene−ethynylene attached to ethynylperylene chromophore) determine temperature dependence electronic absorption process. studied as separate units performed MD simulations for each chromophore at 10 300 K effects on structures. The spectrum nanostar, K, was computed using an ensemble 8000 structures chromophore. Quantum mechanical (QM)...

In the nonresonant regime, molecular conductance decays exponentially with distance, limiting fabrication of efficient semiconductors at nanoscale. this work, we calculate a series acene derivatives connected to gold electrodes using density functional theory (DFT) combined nonequilibrium Green's function (NEGF) formalism. We show that these systems have near length-independent and can exhibit increase length depending on connection electrodes. The analysis orbital energies transmission...

Understanding the interplay between electrical and mechanical properties of DNA molecules is important for design characterization molecular electronic devices, as well understanding role charge transport in biological functions. However, to date, force-induced melting has limited our ability investigate response conductance stretching. Here we present a new molecule–electrode linker based on hairpin-like design, which prevents at end single during stretching by both strands duplex evenly....

Interfacial charge transfer has been an area of intense interest because its relevance in molecular electronics, dye-sensitized solar cells, surface-enhanced Raman scattering (SERS), and photocatalysis. Although the chemical natures both contact linker have shown to play important roles determining properties hybrid dye/molecule–metal oxide complexes, little is known about nature charge-transfer pathways. In this work, we explore detail idea that enhancement are intimately related. To end,...

Single-molecule electrochemical science has advanced over the past decades and now extends well beyond molecular imaging, to electronics functions such as rectification amplification. Rectification is conceptually simplest but involved mostly challenging chemical synthesis of asymmetric structures or materials geometry two enclosing electrodes. Here we propose an experimental theoretical strategy for building tuning in situ (in operando) symmetric environment. The molecules were designed...

Linkers that favor rectification of interfacial electron transfer are likely to be required for efficient photo-driven catalysis multi-electron reactions at electrode surfaces. Design principles discussed, together with the synthesis and characterization a specific pair molecular linkers, related by inversion direction an amide bond in heart molecule. The linkers have terpyridyl group can covalently bind Mn as well-known water oxidation catalyst acetylacetonate allows attachment TiO2...

Design principles for molecules with intrinsic directional charge transport will likely prove crucial breakthroughs in nanotechnology and other emerging fields like biosensors advanced photovoltaics. Here, we perform a systematic computational study to characterize the electronic rectification induced by conformational chemical modifications at low bias potentials elucidate design molecular rectifiers. We donor–bridge–acceptor (D–B–A) systems that consist of phenylene units geometrical...

The single-molecule conductance of hydrogen-bonded and alkane systems are compared in this theoretical investigation. results indicate that for short chains, the H-bonded molecules exhibit larger than alkanes. Although earlier experimental investigations attributed observation to a large density states (DOS) corresponding an occupied molecular orbital below Fermi energy, current work indicates presence Fano resonance transmission function vicinity energy. inclusion is essential understanding...

We explore a connection between the static molecular polarizability and conductance that arises naturally in description of electrified interfaces has recently been explored experimentally. have tested this idea by using measured few different experimental design motifs for junctions relating them to polarizability. Our results show family structurally connected molecules decreases as increases. Within limitations our model, striking result is consistent with physically intuitive picture...

We present a study of the effects chemical modifications on electron transport properties azobenzene molecule, which has been proposed as component light-driven molecular switch. This molecule two stable conformations (cis and trans) in electronic ground state, with considerable differences conductance. The were calculated using first-principles methods combining nonequilibrium Green's function techniques density functional theory. Chemical consist incorporation electron-donating...

Spin polarization in chiral molecules is a magnetic molecular response associated with electron transport and enantioselective bond that occurs even the absence of an external field. An unexpected finding by Santos co-workers reported enantiospecific NMR responses solid-state cross-polarization (CP) experiments, suggesting possible additional contribution to indirect nuclear spin-spin coupling induced presence spin-orbit coupling. Herein we provide theoretical treatment for this phenomenon,...

Characterizing the nano-bio interface has been a long-standing endeavor in quest for novel biosensors, biophotovoltaics, and biocompatible electronic devices. In this context, present computational work on interaction of two peptides, A6K (Ac-AAAAAAK-NH2) A7 (Ac-AAAAAAA-NH2) with semiconducting TiO2 nanoparticles is an effort to understand peptide-metal oxide nanointerface. These investigations were spurred by recent experimental observations that nanostructured metal oxides templated...

A theoretical and computational study of the effect quantum interference on rectification behavior unimolecular devices.