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Supersonic phenomena, the key to extremely low heat loss nano-electronics (Vol. 48 No. 1)
Supersonic solitary waves in nano-electronics crystals show potentials for electric charge or matter transport and energy storage with extremely low heat dissipation
Freak waves, as well as other less striking localised excitations, occur in nature at every scale. The current theory and models of such waves can be applied to physics and, among others, to oceanography, nonlinear optics and lasers, acoustics, plasmas, cosmological relativity and neuro-dynamics. However, they could also play a significant role at the quantum scale in nano-electronics. In a recent study, the authors performed computer simulations to compare two types of localised excitations in nano-electronics. Their findings, published in a recent study, confirm that such localised excitations are natural candidates for energy storage and transport. These, in turn, could lead to applications such as transistors with extremely low heat dissipation not using silicon.
M. G. Velarde, A. P. Chetverikov, W. Ebeling, S. V. Dmitriev and V. D. Lakhno, From solitons to discrete breathers, Eur. Phys. J. B 89, 233 (2016)
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Emergent gain materials for active photonics (Vol. 48 No. 1)
Nowadays semiconductor nanostructures developed by colloidal methods have emerged as an alternative to the classical III-V semiconductors and rare earth technologies to provide active functionalities in photonic devices. Their outstanding optical properties include high absorption cross section, high quantum yield of emission at room temperature, or the capability of tuning the band-gap with the size/base material. As a consequence, these materials have been successfully applied in several fields, such as photodetection, amplification, generation of light or sensing. For these purposes their solution process nature provides a cheap fabrication, and an easy incorporation on a broad range of substrates and photonic structures. This review summarizes the great effort undertaken by the scientific community to construct active photonic devices based on semiconductors fabricated by chemical methods. The work compares the performances demonstrated by semiconductor nanocrystals (colloidal quantum dots, quantum rods and quantum wells) with those provided by organometal halide perovskites, and describes their appropriate integration into photonic architectures (waveguides and cavities) to achieve stimulated emission.
I. Suárez Alvarez, Active photonic devices based on colloidal semiconductor nanocrystals and organometallic halide perovskites, Eur. Phys. J. Appl. Phys. 75, 30001 (2016)
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Unstable radioactive nuclei’s dual traits study in open refereed paper (Vol. 48 No. 1)
HIE-ISOLDE acceleration of radioactive beams to peer into the dual state of matter unique to nuclei.
Radioactive nuclides, found within an atom's core, all share a common feature: they have too many or too few neutrons to be stable. In a new review published recently, the authors explain how overcoming technical difficulties in accelerating such radioactive nuclei beams can help push back the boundaries of nuclear physics research. This fascinating topic is the first EPJ A paper to be subjected to an open referee process, whereby the referee's comments are included. The authors outline how the new CERN project HIE-ISOLDE will reach the energy levels needed to make two nuclei overcome the electric repulsion between them—referred to as the Coulomb barrier. This means that it will be possible to design experimental tools to explore both single-particle and collective degrees of radioactive nuclei freedom. This will improve our understanding of the unique duality in the degrees of freedom, which no other state of matter exhibits. Ultimately, physicists aim to have a “dial-a-radioactive-nuclei beam” of the same quality as stable nuclei beams.
M.J.G. Borge and K. Riisager, HIE-ISOLDE, the project and the physics opportunities, Eur. Phys. J. A 52, 334 (2016)
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Nanoparticles hitchhiking their way along strands of hair (Vol. 48 No. 1)
Massaging hair can help more quickly deliver nanoparticle-based treatment to the roots
In shampoo ads, hair always looks like a shiny, smooth surface. But for physicists peering into microscopes, the hair surface looks much more rugged, as it is made of saw-tooth, ratchet-like scales. In a new theoretical study published recently, the authors have demonstrated that massaging hair can help to apply drug treatment—encapsulated in nanoparticles trapped in the channels formed around individual hairs—to the hair roots. This is because the oscillatory movement of the massaging directs the way these particles are transported. This phenomenon was previously discovered in experiments on pork skin samples, which were conducted by Jürgen Lademann, dermatologist at the Charité clinic in Berlin, Germany, and his team. It is also relevant at the microscopic scale, in the transport on microtubules taking place in two directions between the cells within our bodies. By constrast, these findings could also help find ways of preventing harmful nanoparticles from being transported along hairs into the wrong places.
M. Radtke and R. R. Netz, Ratchet effect for two-dimensional nanoparticle motion in a corrugated oscillating channel, Eur. Phys. J. E 39, 116 (2016)
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