Subscribe to the gold package and get unlimited access to Shamra Academy
Register a new userElectron transport signature of H$_2$ dissociation on atomic gold wires
175
0
0.0
(
0
)
Ask ChatGPT about the research
No Arabic abstract
Non-equilibrium Greens functions calculations based on density functional theory show a direct link between the initial stages of H$_2$ dissociation on a gold atomic wire and the electronic current supported by the gold wire. The simulations reveal that for biases below the stability threshold of the wire, the minimum-energy path for H$_2$ dissociation is not affected. However, the electronic current presents a dramatic drop when the molecule initiates its dissociation. This current drop is traced back to quantum interference between electron paths when the molecule starts interacting with the gold wire.
rate research
Read More
The effect of electron-phonon interactions in the conductance through metallic atomic wires is theoretically analyzed. The proposed model allows to consider an atomic size region electrically and mechanically coupled to bulk electrodes. We show that under rather general conditions the features due to electron-phonon coupling are described by universal functions of the system transmission coefficients. It is predicted that the reduction of the conductance due to electron-phonon coupling which is observed close to perfect transmission should evolve into an enhancement at low transmission. This crossover can be understood in a transparent way as arising from the competition between elastic and inelastic processes.
We have developed a novel method for crystalline hydrogenation of graphene on the nanoscale. Molecular hydrogen was physisorbed at 5 K onto pristine graphene islands grown on Cu(111) in ultrahigh vacuum. Field emission local to the tip of a scanning tunneling microscope dissociates H$_2$ and results in hydrogenated graphene. At lower coverage, isolated point defects are found on the graphene and are attributed to chemisorbed H on top and bottom surfaces. Repeated H$_2$ exposure and field emission yielded patches and then complete coverage of a crystalline $sqrt{3}$ $times$ $sqrt{3}$ R30{deg} phase, as well as less densely packed 3 $times$ 3 and 4 $times$ 4 structures. The hydrogenation can be reversed by imaging with higher bias voltage.
The effect of deconfinement due to finite band offsets on transport through quantum wires with two constrictions is investigated. It is shown that the increase in resonance linewidth becomes increasingly important as the size is reduced and ultimately places an upper limit on the energy (temperature) scale for which resonances may be observed.
We develop a theory of thermal transport of weakly interacting electrons in quantum wires. Unlike higher-dimensional systems, a one-dimensional electron gas requires three-particle collisions for energy relaxation. The fastest relaxation is provided by the intrabranch scattering of comoving electrons which establishes a partially equilibrated form of the distribution function. The thermal conductance is governed by the slower interbranch processes which enable energy exchange between counterpropagating particles. We derive an analytic expression for the thermal conductance of interacting electrons valid for arbitrary relation between the wire length and electron thermalization length. We find that in sufficiently long wires the interaction-induced correction to the thermal conductance saturates to an interaction-independent value.
We present a generic grand-canonical theory for the Peierls transition in atomic wires deposited on semiconducting substrates such as In/Si(111) using a mean-field solution of the one-dimensional Su-Schrieffer-Heeger model. We show that this simple low-energy effective model for atomic wires can explain naturally the occurrence of a first-order Peierls transition between a uniform metallic phase at high-temperature and a dimerized insulating phase at low temperature as well as the existence of a metastable uniform state below the critical temperature.
Log in to be able to interact and post comments
comments
Fetching comments
Sign in to be able to follow your search criteria
