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Headlines 2006

31-12-2006
07-08-2006
J. Gabelli1, G. Fève1, J.-M. Berroir1, B. Plaçais1, A. Cavanna2, B. Etienne2, Y. Jin2, D. C. Glattli1,3

A mixed team from ENS / CNRS / CEA-Saclay (SPEC) of the Pierre Aigrain Laboratory has for the first time highlighted the remarkable behavior of an electronic circuit when its miniaturization is extreme. These results are published in the journal Science. Researchers have shown that the basic laws of electricity, established since 1845, can no longer describe the properties of an electronic circuit when its dimensions reach the nanometer scale. These studies confirm the theoretical predictions of Markus Büttiker (University of Geneva) stated more than ten years ago and never checked.
For more information: the joint press release CEA-CNRS (in french). 
The associated publicaiton: Violation of Kirchhoff's laws for a coherent RC circuit, J. Gabelli et al., ScienceXpress (2006) 1126940.
The Nano-électronique team of DRECAM/SPEC and the "Physique mésoscopique et transport" team of LPA.

11-07-2006
J.-P. Gallien, H. Khodja, Laboratoire Pierre Süe and G. Herzog, Rutgers University, New Brunswick, NJ USA

The Stardust mission, which ended in success on January 15, 2006 after a tour lasting seven years in space, brought back to the Earth the first samples of material taken from the dust coma of comet Wild-2. This comet formed in the Kuiper Belt 4.5 Ga ago. Its orbit far from the Sun helped limit its alteration during its journey and consquently its composition must have been substantially unaltered since its birth. The samples, accordingly, could hold precious clues to the conditions of comet formation. One of the questions that laboratories try to answer concerns the precise concentrations of light elements such as carbon and nitrogen. The results are important in solar system astrophysics, where one seeks to know the redox conditions that prevailed at the time of formation of the first solid materials, as well as in exobiology, for the estimation of the extraterrestrial sources of organic molecules.

 

11-04-2006
Ludovic Douillard et Fabrice Charra, DRECAM/SPCSI/Groupe Nanophotonique

A reduction of the size of a metallic object results in significant changes in its physical properties and in particular its response to an optical excitation. Noticeably, for objects of sizes significantly smaller than the incident wavelength, resonances in the absorption spectrum appear. These, called plasmon resonance, correspond to a process of collective oscillation of the electrons, as described by Mie at the beginning of the 20th century [Mie 1908]. In the case of noble metals, these resonances are in the visible spectrum, a phenomenon known since ancient times for obtaining coloured glasses by inclusion of metallic particles.

Today, the development of nanotechnology involves a great interest in such phenomena, now grouped together in a new topic named plasmonic. Beyond its fundamental aspects, the subject has a wide range of technological applications, from the design of optical components (polarizers, waveguides…) to genetic analysis (biochemical… detector).

 The associated physics involve the coupling between the conduction electrons and the electromagnetic field associated with the incident radiation. For a size lower than the wavelength of the radiation, the electrons are confined within a single object and the electromagnetic field is seen as uniform in space and time. The oscillating nature of the excitation results in a collective and coherent movement of the electrons: the plasmon resonance. The next step is the design of assemblages of such objects, which plasmon modes, under optical excitation, are coupled according to the chosen geometry.

11-04-2006
Ludovic Douillard et Fabrice Charra, DRECAM/SPCSI/Groupe Nanophotonique

A reduction of the size of a metallic object results in significant changes in its physical properties and in particular its response to an optical excitation. Noticeably, for objects of sizes significantly smaller than the incident wavelength, resonances in the absorption spectrum appear. These, called plasmon resonance, correspond to a process of collective oscillation of the electrons, as described by Mie at the beginning of the 20th century [Mie 1908]. In the case of noble metals, these resonances are in the visible spectrum, a phenomenon known since ancient times for obtaining coloured glasses by inclusion of metallic particles.

Today, the development of nanotechnology involves a great interest in such phenomena, now grouped together in a new topic named plasmonic. Beyond its fundamental aspects, the subject has a wide range of technological applications, from the design of optical components (polarizers, waveguides…) to genetic analysis (biochemical… detector).

 The associated physics involve the coupling between the conduction electrons and the electromagnetic field associated with the incident radiation. For a size lower than the wavelength of the radiation, the electrons are confined within a single object and the electromagnetic field is seen as uniform in space and time. The oscillating nature of the excitation results in a collective and coherent movement of the electrons: the plasmon resonance. The next step is the design of assemblages of such objects, which plasmon modes, under optical excitation, are coupled according to the chosen geometry.

07-08-2006
J. Gabelli1, G. Fève1, J.-M. Berroir1, B. Plaçais1, A. Cavanna2, B. Etienne2, Y. Jin2, D. C. Glattli1,3

A mixed team from ENS / CNRS / CEA-Saclay (SPEC) of the Pierre Aigrain Laboratory has for the first time highlighted the remarkable behavior of an electronic circuit when its miniaturization is extreme. These results are published in the journal Science. Researchers have shown that the basic laws of electricity, established since 1845, can no longer describe the properties of an electronic circuit when its dimensions reach the nanometer scale. These studies confirm the theoretical predictions of Markus Büttiker (University of Geneva) stated more than ten years ago and never checked.
For more information: the joint press release CEA-CNRS (in french). 
The associated publicaiton: Violation of Kirchhoff's laws for a coherent RC circuit, J. Gabelli et al., ScienceXpress (2006) 1126940.
The Nano-électronique team of DRECAM/SPEC and the "Physique mésoscopique et transport" team of LPA.

 

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