Tuning the through-bond interaction in a two-centre problem

Levstein, Patricia R.; Pastawski, Horacio M.; D’Amato, Jorge L.

doi:10.1088/0953-8984/2/7/009

Cited by 58 publications

(69 citation statements)

References 30 publications

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“…This survival collapse is identified with a destructive interference between the pure survival amplitude, i.e., the SC-FGR component, and the return amplitude, associated with higher orders in a perturbation theory. This striking quantum phenomenon can be seen as a dynamical version of the antiresonance that has been described for steady state observables [23,24,25]. Now, the destructive interference is also due to the splitting of the wave among two different families of pathways in space.…”

Section: Introductionmentioning

confidence: 80%

Non-Markovian decay beyond the Fermi Golden Rule: Survival collapse of the polarization in spin chains

Fiori

Pastawski

2006

Chemical Physics Letters

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The decay of a local spin excitation in an inhomogeneous spin chain is evaluated exactly: I) It starts quadratically up to a spreading time tS. II) It follows an exponential behavior governed by a self-consistent Fermi Golden Rule. III) At longer times, the exponential is overrun by an inverse power law describing return processes governed by quantum diffusion. At this last transition time tR a survival collapse becomes possible, bringing the polarization down by several orders of magnitude. We identify this strongly destructive interference as an antiresonance in the time domain. These general phenomena are suitable for observation through an NMR experiment.

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Section: Introductionmentioning

confidence: 80%

Non-Markovian decay beyond the Fermi Golden Rule: Survival collapse of the polarization in spin chains

Fiori

Pastawski

2006

Chemical Physics Letters

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“…In a 1-D case, this is G 1N (where N is the number of sites of the system) and can be calculated through a decimation procedure. [37] While this can be readily generalized to deal with finite systems of any dimension, not all formulations result numerically stable in presence of strong disorder or band gaps. [42] We will present a particular algorithm that is stable in such conditions.…”

Section: Multi-terminal D'amato-pastawski Modelmentioning

confidence: 99%

Generalized multi-terminal decoherent transport: recursive algorithms and applications to SASER and giant magnetoresistance

Cattena

Fernández-Alcázar

Bustos-Marún

et al. 2014

J. Phys.: Condens. Matter

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Decoherent transport in mesoscopic and nanoscopic systems can be formulated in terms of the D'Amato-Pastawski (DP) model. This generalizes the Landauer-Büttiker picture by considering a distribution of local decoherent processes. However, its generalization for multi-terminal setups is lacking. We first review the original two-terminal DP model for decoherent transport. Then, we extend it to a matrix formulation capable of dealing with multi-terminal problems. We also introduce recursive algorithms to evaluate the Green's functions for general banded Hamiltonians as well as local density of states, effective conductances and voltage profiles. We finally illustrate the method by analyzing two problems of current relevance. 1) Assessing the role of decoherence in a model for phonon lasers (SASER). 2) Obtaining the classical limit of Giant Magnetoresistance from a spin-dependent Hamiltonian. The presented methods should pave the way for computationally demanding calculations of transport through nanodevices, bridging the gap between fully coherent quantum schemes and semiclassical ones.

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“…The second term contains a virtual exploration into the first polaronic excitation. It is noteworthy that when Γ = 0, this Green function would cancel out at an intermediate energy giving rise to an antiresonance [14,13]. This concept extends the spectroscopic Fano-resonances [15] to the problem of conductance [16].…”

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confidence: 73%

“…The number n of phonons is the vertical dimension [11,12]. The horizontal dangling chains can be eliminated through a decimation procedure [10,13] leading to an effective Hamiltonian:H e−ph = n≥0 {[E 0 + nhω 0 + Σ n (ε)] |0, n 0, n| −− √ n + 1V g (|0, n + 1 0, n| + |0, n 0, n + 1|)},The electron hopping into the electrodes is taken into account by the ε-dependence of the retarded self-energy 1 …”

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confidence: 99%

Tuning a resonance in Fock space: Optimization of phonon emission in a resonant-tunneling device

2001

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Phonon-assisted tunneling in a double barrier resonant tunneling device can be seen as a resonance in the electron-phonon Fock space which is tuned by the applied voltage. We show that the geometrical parameters can induce a symmetry condition in this space that can strongly enhance the emission of longitudinal optical phonons. For devices with thin emitter barriers this is achieved by a wider collector barrier.Progress in mesoscopic semiconductor devices [1] and molecular electronics [2] is driven by the need of miniaturization and the wealth of new physics provided by coherent quantum phenomena. A fundamental idea behind these advances was Landauer's view that conductance is transmittance [3,4]. Hence, the typical conductance peaks and valleys, observed when some control parameter is changed, are seen as fringes in an interferometer. However, the many-body electron-electron (ee) and electron-phonon (e-ph) interactions restrict the use of this picture. The e-e effects received much attention in different contexts [1]. While interest on e-ph interaction remained mainly focused on double barrier Resonant Tunneling Devices (RTD) [5], where phononassisted tunneling shows up as a satellite peak in a valley of the current-voltage (I-V) curve, recent observation of electro-mechanical effects in molecular electronics [6] requires a reconsideration of the e-ph problem. Theory evolved from a many-body Green's function in a simplified model for the polaronic states [7] to quantum and classical rate equations approach [8]. The latter uses an incoherent description of the e-ph interaction by adopting an imaginary self-energy correction to the electronic states [9,10].In this article, we analyze a quantum coherent solution of transport with e-ph interaction. We resort to a mapping of the many-body problem into a one-body scattering system where each phonon mode adds a new dimension to the electronic variable [11,12]. Transmission of electrons between incoming and outgoing channels with different number of phonons are then used in a Landauer's picture where the only incoherent processes occur inside the electrodes. This allows to develop the concept of resonance in the e-ph Fock space and the identification of the control parameters that optimize the coherent processes leading to a maximized phonon emission. It also gives a clue as to how "decoherence" arise within an exact many-body description. As an application, we consider a RTD phonon emitter where the relevant parameters are best known. There, the first polaronic excitation serves as an "intermediate" state for the phonon emission. An electron with kinetic energy ε ≤ ε F and potential energy eV in the emitter decays through tunneling into an electron with energy ε + eV−hω 0 in the collector plus a longitudinal optical (LO) phonon. The tuning parameter is the applied voltage while the optimization of phonon emission requires the tailoring of the tunneling rates.Let us consider a minimal Hamiltonian:where c + j and c j are electron creation and annihilation operators at s...

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Tuning the through-bond interaction in a two-centre problem

Cited by 58 publications

References 30 publications

Non-Markovian decay beyond the Fermi Golden Rule: Survival collapse of the polarization in spin chains

Non-Markovian decay beyond the Fermi Golden Rule: Survival collapse of the polarization in spin chains

Generalized multi-terminal decoherent transport: recursive algorithms and applications to SASER and giant magnetoresistance

Tuning a resonance in Fock space: Optimization of phonon emission in a resonant-tunneling device

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