Shot-noise control in ac-driven nanoscale conductors

Camalet, S.; Kohler, Sigmund; Hänggi, Peter

doi:10.1103/physrevb.70.155326

Cited by 62 publications

(104 citation statements)

References 71 publications

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“…[10,16] to provide explicit expressions for the current through time-dependent nanoscale conductors and its zero-frequency noise. With this formalism, the conductance properties of bridged molecular wires have been investigated.…”

Section: Discussionmentioning

confidence: 99%

“…we find after some algebra that it assumes the commonly expected "scattering form" [13] but with periodically time-dependent transmission probabilities and, as well, an additional contribution that accounts for a T -periodic charging/discharging of the wire [10,16]. Only the former contributes to the time-averaged current…”

Section: Floquet Transport Theorymentioning

confidence: 99%

“…Therefore, it is possible to characterize the noise level by the timeaveraged zero-frequency noise,S L = dτ T 0 dt S L (t, t−τ )/T . Since the total charge is conserved, we findS L =S R =S, where [10,16] …”

Section: Floquet Transport Theorymentioning

confidence: 99%

“…This suggests utilizing the tools that have been acquired in that area, thus, developing a transport formalism that combines Floquet theory for a driven molecule with the many-particle description of transport through a system that is coupled to ideal leads [8,10,16].…”

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confidence: 99%

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Molecular Wires in Electromagnetic Fields

Kohler

Lehmann

Strass

et al. 2004

Advances in Solid State Physics 44

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Abstract. We investigate the role of external electromagnetic fields on the conduction properties of bridged molecular wires. In particular, it is analyzed quantitatively how resonant excitations of electrons enhance the dc current and, simultaneously, lower the noise level of the current. The results from an exact numerical treatment are in good agreement with those obtained within an approximation scheme applicable at resonances.Thirty years ago, Aviram and Ratner proposed in a seminal work [1] to build elements of electronic circuits-in their case a rectifier-with single molecules. In the present days their vision starts to become reality and the experimental and theoretical study of such systems enjoys a vivid activity [2][3][4]. Recent experimental progress has enabled reproducible measurements [5,6] of weak tunneling currents through molecules which are coupled by chemisorbed thiol groups to the gold surface of external leads.Typical energy scales in molecules are in the optical and the infrared regime, where basically all of the today's lasers operate. Hence, lasers represent a natural possibility to control atoms or molecules and also currents through them. It is for example possible to induce by the laser field an oscillating current in the molecule which under certain asymmetry conditions is rectified by the molecule. This results in a directed electron transport even in the absence of any applied voltage [7,8]. Another theoretically predicted effect is the current suppression by the laser field [9,10] which offers the possibility to control both the average current and the current noise.Since the considered frequencies lie below typical plasma frequencies of metals, the laser light will be reflected at the metal surface, i.e., it does not penetrate the leads. Consequently, we assume that the leads' bulk properties are essentially unaffected by the laser field-in particular each lead remains close to equilibrium. Thus, it is sufficient to consider the influence of the driving solely in the molecule Hamiltonian. In addition, the energy of infrared light quanta is by far smaller than the work function of a common metal, which is of the order of 5 eV. This prevents the generation of a photo current, which otherwise would dominate the effects discussed below. For a quantitative description of an experiment, it might be necessary to take into account also the influence of the laser on the leads.Most theoretical descriptions of the molecular conductivity in static situations are based on a scattering approach [11][12][13], or assume that the un-

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Section: Discussionmentioning

confidence: 99%

Section: Floquet Transport Theorymentioning

confidence: 99%

Section: Floquet Transport Theorymentioning

confidence: 99%

mentioning

confidence: 99%

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Molecular Wires in Electromagnetic Fields

Kohler

Lehmann

Strass

et al. 2004

Advances in Solid State Physics 44

Self Cite

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show abstract

“…It has been shown [18,19] that for large driving frequencies X, the time-dependent system can be approximated by a static one with renormalized parameters. The starting point of this approximation scheme is the unitary transformation…”

Section: High-frequency Regimementioning

confidence: 99%