Theoretical description of quasiresonant charge exchange in atom-surface collisions

Shao, Hongxiao; Langreth, David C.; Nordlander, Peter

doi:10.1103/physrevb.49.13948

Cited by 34 publications

(24 citation statements)

References 20 publications

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“…This as well as appearance of quantized states, due to confinement [5], would obviously affect electron capture and loss probabilities; capture or loss would, e.g., be inhibited in the bandgap region, and the description of it would need to be different. In the case of discrete states, non-resonant velocity-dependent charge transfer processes [29][30][31] may play a role as for dielectric surfaces and should be treated using a molecular description, as this has been done also for ionic solids [32,33]. Finally, it has also been suggested [14] that perhaps defect sites on the cluster or interaction with adatoms, atoms at kinks, and boundaries may somehow play a role.…”

Section: Resultsmentioning

confidence: 99%

Electron transfer processes on Au nanoclusters supported on graphite

et al. 2013

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Electron transfer processes play an important role in surface chemistry. This paper presents results of a study of changes in resonant electron transfer processes, as a function of gold cluster sizes, on the example of electron transfer between Li + ions scattered on Au clusters on highly oriented pyrolytic graphite (HOPG). The gold nanoclusters were grown on lightly sputtered HOPG surface in order to obtain a wide coverage distribution of clusters. The growth of clusters was monitored by scanning tunneling microscopy. We found that electron transfer is much more probable on small clusters, whose lateral size is of the order of 2 to 3 nm and height in the 1-nm range, than on bulk Au or thin Au films. A comparison with Au clusters grown on the semiconducting titania did not reveal significant differences with HOPG.

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Section: Resultsmentioning

confidence: 99%

Electron transfer processes on Au nanoclusters supported on graphite

et al. 2013

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“…This contrasts with their equilibrium properties, which are largely well understood [1], or can be investigated within a number of highly accurate methods, such as the numerical renormalization group method (NRG) [2][3][4][5], the continuous time quantum Monte Carlo (CTQMC) approach [6], the density matrix renormalization group [7], or the Bethe ansatz method [8,9]. Quantum impurity models far from equilibrium are of direct relevance to several fields of research, including charge transfer effects in lowenergy ion-surface scattering [10][11][12][13][14][15][16][17], transient and steady state effects in molecular and semiconductor quantum dots [18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36], and also in the context of dynamical mean field theory (DMFT) of strongly correlated lattice models [37][38][39], as generalized to nonequilibrium [40][41][42]. In the latter, further progress hinges on an accurate non-perturbative solution for the nonequilibrium Green functions of an effective quantum impurity model.…”

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confidence: 99%

Time Evolution of the Kondo Resonance in Response to a Quench

Nghiem

Costi

2017

Phys. Rev. Lett.

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We investigate the time evolution of the Kondo resonance in response to a quench by applying the timedependent numerical renormalization group (TDNRG) approach to the Anderson impurity model in the strong correlation limit. For this purpose, we derive within TDNRG a numerically tractable expression for the retarded two-time nonequilibrium Green function G(t + t , t), and its associated time-dependent spectral function, A(ω, t), for times t both before and after the quench. Quenches from both mixed valence and Kondo correlated initial states to Kondo correlated final states are considered. For both cases, we find that the Kondo resonance in the zero temperature spectral function, a preformed version of which is evident at very short times t → 0 + , only fully develops at very long times t 1/T K , where T K is the Kondo temperature of the final state. In contrast, the final state satellite peaks develop on a fast time scale 1/Γ during the time interval −1/Γ t +1/Γ, where Γ is the hybridization strength. Initial and final state spectral functions are recovered in the limits t → −∞ and t → +∞, respectively. Our formulation of two-time nonequilibrium Green functions within TDNRG provides a first step towards using this method as an impurity solver within nonequilibrium dynamical mean field theory.Introduction.-The nonequilibrium properties of strongly correlated quantum impurity models continue to pose a major theoretical challenge. This contrasts with their equilibrium properties, which are largely well understood [1], or can be investigated within a number of highly accurate methods, such as the numerical renormalization group method (NRG) [2][3][4][5], the continuous time quantum Monte Carlo (CTQMC) approach [6], the density matrix renormalization group [7], or the Bethe ansatz method [8,9]. Quantum impurity models far from equilibrium are of direct relevance to several fields of research, including charge transfer effects in lowenergy ion-surface scattering [10][11][12][13][14][15][16][17], transient and steady state effects in molecular and semiconductor quantum dots [18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36], and also in the context of dynamical mean field theory (DMFT) of strongly correlated lattice models [37][38][39], as generalized to nonequilibrium [40][41][42]. In the latter, further progress hinges on an accurate non-perturbative solution for the nonequilibrium Green functions of an effective quantum impurity model. Such a solution, beyond allowing timeresolved spectroscopies of correlated lattice systems within DMFT to be addressed [43][44][45][46][47], would also be useful in understanding time-resolved scanning tunnelling microscopy of nanoscale systems [48] and proposed cold atom realizations of Kondo correlated states [49][50][51][52], which could be probed with real-time radio-frequency spectroscopy [53][54][55].In this Letter, we use the time-dependent numerical renormalization group (TDNRG) approach [56][57][58][59][60][61][62] to calculate the retarded two-time ...

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“…Now, the velocity of an atomic ion colliding with a surface is the parameter which governs the neutralization dynamics of the projectile [13,14]. Analogously, during the collision of a cluster the electronic charge may jump from the cluster to the surface and backwards.…”

Section: Femtosecond Neutralization Dynamics In Cluster-solid Surfacementioning

confidence: 97%

Femtosecond Neutralization Dynamics in Cluster-Solid Surface Collisions

et al. 1997

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Experimental results for the relative electron emission yields g͑N͒ of charged clusters colliding at low energies with different surfaces are presented. For fixed collision energy a remarkable cluster size dependence of g͑N͒ is obtained using highly oriented pyrolytic graphite as target. By studying theoretically the collision process within a microscopic model we find that the nonadiabatic survival probability of the charged clusters shows the same behavior as g͑N͒. Thus, g͑N͒ reflects the femtosecond neutralization dynamics during the collision, which may result in damped Stückelberg oscillations for targets with narrow densities of states. [S0031-9007(97)04139-2] PACS numbers: 79.20. Rf, 34.50.Dy, 36.40.Wa Quantum effects observed when two macroscopic objects interact via a tunneling gap are always exciting as they might be important for future nanoelectronic devices. In addition they sometimes allow intriguing insight into the physics of quantum states induced by the charge confinement in a system of reduced dimensionality. As a matter of fact, however, the dynamics of the electron motion usually remains hidden due to the extremely short time scales involved. Only recently the pumpprobe techniques with femtosecond laser light pulses have started to give some progress in the understanding of such processes.Here we will raise the question of whether the transient character of a collision process of a charged metal atom cluster with a solid surface might elucidate the dynamics of the electron motion between the two partners. Will there be a single electron jump as in a classical picture, or might there be a resonant tunneling process where the charge density-once the collision partners overcome a minimum threshold distance-fluctuates between cluster and surface?So far, this question has not been tackled. A variety of collision experiments between clusters and solid surfaces were performed during the last decades. These can be grouped into investigations involving (i) surface modification by cluster bombardment or deposition [1,2], (ii) scattering of intact species and their fragments [3,4], and (iii) electron emission [5][6][7]. Such studies gave, for instance, insight into the stability of small particles and, to a certain extent, their geometry; energetic cluster impact can modify the formation of thin films. During energetic impact there exist nonequilibrium conditions similar to those in shock tubes, but on a very different time scale, a femtosecond scale. New types of chemical reactions, characterized by extremely high density, pressure, and kinetic temperature, are expected to occur. All these experiments give no hints of possible quantum effects, which are the topic of this Letter.The setup of the experiment for collision induced electron emission measurements will be described in detail elsewhere [8]. In short, the clusters are produced in a source of the PACIS type [9]. After acceleration to their final collision energy E coll , they are mass separated in a Wien velocity filter (Colutron 600 B) which...

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Theoretical description of quasiresonant charge exchange in atom-surface collisions

Cited by 34 publications

References 20 publications

Electron transfer processes on Au nanoclusters supported on graphite

Electron transfer processes on Au nanoclusters supported on graphite

Time Evolution of the Kondo Resonance in Response to a Quench

Femtosecond Neutralization Dynamics in Cluster-Solid Surface Collisions

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