From transistor to nanotube

We present here the main steps in the evolution of the transistor, since the tremendous invention of such a device and the introduction of the integrated circuit. We will then recall the main steps of Moore's law development. Nanotechnology began at the very beginning of the 21st century. Two aspects are presented in this article: the first, called ‘More Moore’, consists in continuing the laws of scale up to the physical limits; the second aspect, called ‘beyond CMOS’ explores new concepts such as spintronics, moletronics, nanotronics and other types of molecular electronics. To cite this article: J.-C. Boudenot, C. R. Physique 9 (2008).     

Semiconductor heterostructures for spintronics and quantum information

A selection of optical experiments is presented, demonstrating the utility of semiconductors in two novel areas of research: spintronics and quantum information. First we show examples of spin manipulation in semiconductor quantum wells. The light is used to generate a spin polarization and to detect it. Next we discuss application of optical methods in studies of carrier-induced ferromagnetism in quantum wells. Finally, we present examples of single quantum dot spectroscopy related to perspectives of application of quantum dots in quantum information, and, in particular, the use of photon correlation measurements as a tool to study the quantum dot excitation mechanisms. To cite this article: J.A. Gaj et al., C. R. Physique 8 (2007).     

Quantum transitions in bilayer states

The possible phase transitions when two layers at filling factor ν_t=1 are gradually separated are studied in this article. In the bosonic case the system should undergo a pairing transition from a Fermi liquid to an incompressible state. In the Fermionic case, the state evolves from an incompressible (1,1,1) state to a Fermi liquid. It is speculated that there is an intermediate phase involving charge two quasiparticles. To cite this article: V. Pasquier, C. R. Physique 3 (2002) 709–715.     

Stresses in compressed bubble rafts

We present a simple geometric method to determine the stress field in a compressed bubble raft. We show that bubble rafts exhibit arches phenomena as do granular materials, and examine the relaxation of stresses following a T₁ transformation. To cite this article: C. Ybert, J.-M. di Meglio, C. R. Physique 3 (2002) 555–559.     

Life prediction for HLW containers – issues related to long-term extrapolation of corrosion resistance

Traditionally, the corrosion behaviour of container materials can be predicted by extrapolation from relatively short-term experiments. Approaches to life prediction are described for two kinds of materials: carbon steel (corrosion allowance material) which must resist general corrosion, and passive materials (corrosion-resistant materials) which may suffer localized corrosion phenomena (pitting and crevice corrosion). The current theoretical and empirical basis for extrapolating the behavior of these materials to long periods emphasizes the significant gaps in understanding. To improve the credibility of life prediction, and to prove the robustness of geological disposal systems, predictive models based on mechanistic understanding are needed. This work is probably more difficult for the corrosion-resistant materials than for corrosion-allowance materials. To cite this article: J.-M. Gras, C. R. Physique 3 (2002) 891–902.     

Lithium absorption on single-walled boron nitride,aluminum nitride,silicon carbide and carbon nanotubes: A first-principles study

Using the DFT-B3LYP calculations we investigate the adsorption of Li atom on CNT, BNNT, AlNNT and SiCNT. We found that Li atom can be chemisorbed on zig-zag SiCNT with binding energy of −2.358 eV and charge transfer of 0.842 |e|, which are larger than the results of other nanotubes. The binding energy of Li on SiCNT is foun to be stronger than activation energy barrier indicating that Li metal could be well dispersed on SiCNTs. Furthermore, the average voltage caused by the lithium adsorption on SiCNT demonstrated that SiCNTs could exhibit as a stable anode similar to the lithium metal anode. The binding nature has been rationalized by analyzing the electronic structures. Our findings demonstrate that Li-BNNT, Li-SiCNT and Li-AlNNT systems exhibit spin polarized behaviors and can fascinating potential application in future spintronics. Also, Li-SiCNT system with rather small band gap might be a promising material for optical applications and active molecule in its environment.     

Les matériaux magnétiques hyperfréquences à l'ère des métamatériaux

This article investigates the advances brought by metamaterials in order to obtain attractive magnetic microwave properties. Can magnetic metamaterials outperform conventional soft magnetic materials? In the case where permeability levels and bandwidth are the key figures of merit, it is acknowledged that copper-based metamaterials can exceed the performance of soft magnetic materials, but only at operating frequencies above 10 GHz. As for low frequency operation, magnetic metamaterials may also be preferred to conventional magnetic materials when requirements include excellent temperature stability or immunity to external magnetic fields. However, in many cases, metamaterials need to include certain conventional magnetic constituents in order to compete with conventional magnetic materials. Several types of metamaterials containing conventional magnetic inclusions and well suited for industrial production are presented. Last but not least, it is underlined that the investigations on metamaterials are beneficial to scientific exchanges between scientists from different areas. To cite this article: O. Acher, C. R. Physique 10 (2009).     

Review: Rheological properties of biological materials

Eukaryotic cells and biological materials are described from a rheological point of view. Single cells possess typical microrheological properties which can affect cell behaviour, in close connection with their adhesion properties. Single cell properties are also important in the context of multicellular systems, i.e. in biological tissues. Results from experiments are analyzed and models proposed both at the cellular scale and the macroscopic scale. To cite this article: C. Verdier et al., C. R. Physique 10 (2009).     

Covalent clusters-based materials

We review the properties of covalent clusters-based materials in relation to free cluster properties, namely carbon, silicon and mixed carbon clusters. These properties are understood in terms of quantum size especially the so called rehybridization effect. We show that low energy cluster beam deposition is a powerful technique to prepare unusual bonding. To cite this article: P. Mélinon et al., C. R. Physique 3 (2002) 273–288.     

New conditionings for separated long-lived radionuclides

Long-lived radionuclides such as I¹²⁹, Cs¹³⁵ and minor actinides can be incorporated in crystalline structures of several specific materials with high chemical durability. Apatites, zirconolite, monazites, thorium phosphate-diphosphate and hollandite are being studied at the CEA and among a scientific research group called NOMADE. A first step is devoted to the scientific feasibility dealing with elaboration and characterization of non-radioactive materials and studies of their chemical durability and radiation stability. Development of apatite for iodine and minor actinides, zirconolite for minor actinides, monazite for trivalent actinides and thorium phosphate–diphosphate for tetravalent actinides has reached the scientific feasibility. Cs conditioning in hollandite and phosphate minerals needs further studies. To cite this article: C. Guy et al., C. R. Physique 3 (2002) 827–837.     

Laser diode reliability: crystal defects and degradation modes

Degradation analysis is a crucial issue for the improvement of high power laser diodes. Degradation occurs in three different modes: rapid, gradual and catastrophic. It can be located inside the cavity or at the facet mirrors. Each type of degradation presents its own signature and different crystal defects appear associated with them. The main physical mechanisms responsible for laser degradation are analysed showing the relation between the main degradation modes and the different materials properties of the laser structures. To cite this article: J. Jiménez, C. R. Physique 4 (2003).     

Review of photorefractive materials: an application to laser beam cleanup

Nonlinear photorefractive materials are well suited to record dynamic volume holograms using the wave mixing of coherent laser beams. The photo-induced index modulation is due to a space charge field which modulates the crystal refractive index. The basic phenomena and beam interactions are reviewed for different types of materials operating in the visible and near infrared. In particular, we outline their ability to amplify a low intensity signal beam due to the intensity transfer of a spatially multimode pump beam. We apply this interaction to the cleanup of a multimode large core fiber amplifier. This class of nonlinear materials contribute to extending the performances of laser sources for advanced applications of photonics. To cite this article: L. Lombard et al., C. R. Physique 8 (2007).     

Hybrid bulk heterojunction solar cells based on blends of TiO2 nanorods and P3HT

Over the past decades, organic solar cells based on semiconducting polymers or small molecules have become a promising alternative to traditional inorganic photovoltaic devices. However, to address the intrinsic limitations of organic materials, such as charge separation yield, charge transport and durability, new strategies based on hybrid organic/inorganic materials have been explored. One such approach exploits mesoporous inorganic nanostructures as electron acceptors, which takes advantage of the potential to control the active layer structure and interface morphology through nanoparticle synthesis and processing. In this work, the potential of hybrid photovoltaics will be discussed and illustrated through a recent study of bulk heterojunction systems based on the blend of TiO₂ nanorods with a conjugated polymer. To cite this article: J. Bouclé et al., C. R. Physique 9 (2008).     

Recent applications and current trends in Cultural Heritage Science using synchrotron-based Fourier transform infrared micro-spectroscopy

Synchrotron-based Fourier transform infrared micro-spectroscopy (SR-FTIR) is one of the emerging techniques increasingly employed for Cultural Heritage analytical science. Such a technique combines the assets of FTIR spectroscopy (namely, the identification of molecular groups in various environments: organic/inorganic, crystallized/amorphous, solid/liquid/gas), with the extra potential of chemical imaging (localization of components + easier data treatment thanks to geographical correlations) and the properties of the synchrotron source (namely, high brightness, offering high data quality even with reduced dwell time and reduced spot size).This technique can be applied to nearly all kind of materials found in museum objects, going from hard materials, like metals, to soft materials, like paper, and passing through hybrid materials such as paintings and bones. The purpose is usually the identification of complex compositions in tiny, heterogeneous samples.Recent applications are reviewed in this article, together with the fundamental aspects of the infrared synchrotron source which are leading to such improvements in analytical capabilities. A recent example from the ancient Buddhist paintings from Bamiyan is detailed. Emphasis is made on the true potential offered at such large scale facilities in combining SR-FTIR microscopy with other synchrotron-based micro-imaging techniques. To cite this article: M. Cotte et al., C. R. Physique 10 (2009).     

Single photon emission from a single molecule

Photon emission from a single molecule at room temperature exhibits nonclassical features. Continuous wave fluorescence excitation provides antibunching in the emitted photons sequence as a signature of the property to only emit one photon at a time. A short pulsed excitation can then produce single photons on demand, with an overall quantum efficiency up to 4.5% in our experimental setup. Direct measurement of the Mandel parameter Q(T) for an observation period of duration T follows a subpoissonian statistics on short time scale and superpoissonian statistics on longer time scale. The latter is attributed to blinking in the fluorescence due to the occurence of a metastable molecular triplet state. To cite this article: F. Treussart et al., C. R. Physique 3 (2002) 501–508.     

Charge modulation of magnetization in X-doped MgO nanotube clusters (X=C,N)

First-principles calculations based on density functional theory are performed to study the magnetic and electronic properties of X-doped 8×7 MgO nanotube clusters (X=C, N). The N dopant easily occupies the O-site at the edge of MgO nanotube, embracing neutral or charged defect state, and induces notable magnetization in N-doped MgO tubular cluster. More important, this p-electron magnetization can be significantly modulated as the charged state of the defect changes. Regarding C doping, impurity atom readily substitute the Mg atom located at the edge of MgO nanotube to form neutral defect, and net magnetization is found to be zero. The calculated electron densities of states show that the O-site N doping at the edge greatly narrows or even destroys band-gap, while it enlarges somewhat for the Mg-site C doping at the edge. The results are likely to stimulate a promising class of materials for various applications ranging from spintronics to magneto-optics.     

Optical waveguides in laser crystals

This article reviews the recent research on different types of planar and channel crystalline optical waveguides, fabrication methods such as liquid phase epitaxy, pulsed laser deposition, thermal bonding, reactive ion or ion beam etching, wet chemical etching, ion in-diffusion, proton exchange, ion beam implantation, and femtosecond laser writing, as well as waveguide laser operation of rare-earth and transition-metal ions in oxide crystalline materials such as Al₂O₃, Y₃Al₅O₁₂, YAlO₃, KY(WO₄)₂, and LiNbO₃. To cite this article: M. Pollnau, Y.E. Romanyuk, C. R. Physique 8 (2007).     

Epitaxial self-organization: from surfaces to magnetic materials

Self-organization of magnetic materials is an emerging and active field. An overview of the use of self-organization for magnetic purposes is given, with a view to illustrate aspects that cannot be covered by lithography. A first set of issues concerns the quantitative study of low-dimensional magnetic phenomena (1D and 0D). Such effects also occur in microstructured and lithographically-patterned materials but cannot be studied in these because of the complexity of such materials. This includes magnetic ordering, magnetic anisotropy and superparamagnetism. A second set of issues concerns the possibility to directly use self-organization in devices. Two sets of examples are given: first, how superparamagnetism can be fought by fabricating thick self-organized structures, and second, what new or improved functionalities can be expected from self-organized magnetic systems, like the tailoring of magnetic anisotropy or controlled dispersion of properties. To cite this article: O. Fruchart, C. R. Physique 6 (2005).     

History and results of the Riga dynamo experiments

On 11 November 1999, a self-exciting magnetic eigenfield was detected for the first time in the Riga liquid sodium dynamo experiment. We report on the long history leading to this event, and on the subsequent experimental campaigns which provided a wealth of data on the kinematic and the saturated regime of this dynamo. The present state of the theoretical understanding of both regimes is delineated, and some comparisons with other laboratory dynamo experiments are made. To cite this article: A. Gailitis et al., C. R. Physique 9 (2008).