arXiv subjects

Sébastien Camalet

Publications and source records attributed to Sébastien Camalet.

5 recordsLinked to original sources

arXiv2004

Shot noise control in ac-driven nanoscale conductors

We derive within a time-dependent scattering formalism expressions for both the current through ac-driven nanoscale conductors and its fluctuations. The results for the time-dependent current, its time average, and, above all, the driven shot noise properties assume an explicit and serviceable form by relating the propagator to a non-Hermitian Floquet theory. The driven noise cannot be expressed in terms of transmission probabilities. The results are valid for a driving of arbitrary strength and frequency. The connection with commonly known approximation schemes such as the Tien-Gordon approach or a high-frequency approximation is elucidated together with a discussion of the corresponding validity regimes. Within this formalism, we study the coherent suppression of current and noise caused by properly chosen electromagnetic fields.

cond-mat.mes-hall↗

arXiv2003

Charge transport through a molecule driven by a high-frequency field

We study the current and the associated noise for the transport through a two-site molecule driven by an external oscillating field. Within a high-frequency approximation, the time-dependent Hamiltonian is mapped to a static one with effective parameters that depend on the driving amplitude and frequency. This analysis allows an intuitive physical picture explaining the nontrivial structure found in the noise properties as a function of the driving amplitude. The presence of dips in the Fano factor permits a control of the noise level by means of an appropriate external driving.

cond-mat.mes-hall↗

arXiv2002

Current Noise in ac-Driven Nanoscale Conductors

The theory for current fluctuations in ac-driven transport through nanoscale systems is put forward. By use of a generalized, non-Hermitian Floquet theory we derive novel explicit expressions for the time-averaged current and the zero-frequency component of the power spectrum of current fluctuations. A distinct suppression of both the zero-frequency noise and the dc-current occurs for suitably tailored ac-fields. The relative level of transport noise, being characterized by a Fano factor, can selectively be manipulated by ac-sources; in particular, it exhibits both characteristic maxima and minima near current suppression.

cond-mat.mes-hall↗

arXiv2002

Resonant laser excitation of molecular wires

We investigate the influence of external laser excitations on the average current through bridged molecules. For the computation of the current, we use a numerically very efficient formalism that is based on the Floquet solutions of the time-dependent molecule Hamiltonian. It is found that the current as a function of the laser frequency exhibits characteristic peaks originating from resonant excitations of electrons to bridge levels which are unoccupied in the absence of the radiation. The electrical current through the molecule can exhibit a drastic enhancement by several orders of magnitude.

physics.chem-ph↗

arXiv2002

Laser controlled molecular switches and transistors

We investigate the possibility of optical current control through single molecules which are weakly coupled to leads. A master equation approach for the transport through a molecule is combined with a Floquet theory for the time-dependent molecule. This yields an efficient numerical approach to the evaluation of the current through time-dependent nano-structures in the presence of a finite external voltage. We propose tunable optical current switching in two- and three-terminal molecular electronic devices driven by properly adjusted laser fields, i.e. a novel class of molecular transistors.

physics.chem-ph↗