Catálogo de publicaciones - revistas

<jats:title>Making the forbidden allowed</jats:title><jats:p>Spontaneous emission, in which an excited electron lowers its energy by emitting a photon, is a fundamental process in light-matter interactions. In principle, the electron can relax from the excited state to any unoccupied lower energy level. In practice, however, most of these transitions are too slow and so are effectively forbidden. Rivera<jats:italic>et al.</jats:italic>show theoretically that the plasmonic excitations associated with two-dimensional materials can be used to enhance and control the light-matter interaction. Transitions that were once considered forbidden can thus be accessed, opening up the entire spectrum of an optical emitter.</jats:p><jats:p><jats:italic>Science</jats:italic>, this issue p.<jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6296" page="263" related-article-type="in-this-issue" vol="353" xlink:href="10.1126/science.aaf6308">263</jats:related-article></jats:p>

<jats:title>Turning the corner</jats:title> <jats:p> The Antarctic ozone hole is finally showing signs of disappearing, nearly 30 years after the Montreal Protocol came into effect. The Montreal Protocol, an international treaty that phased out the production of many of the human-made compounds responsible for stratospheric ozone destruction, is widely considered to be the most important and successful international environmental agreement. For years, it has slowed the rate of stratospheric ozone depletion, and now there are signs that the ozone abundance over Antarctica has begun to increase. Solomon <jats:italic>et al.</jats:italic> present observational data and model results to illustrate the trends and diagnose their causes. </jats:p> <jats:p> <jats:italic>Science</jats:italic> , this issue p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6296" page="269" related-article-type="in-this-issue" vol="353" xlink:href="10.1126/science.aae0061">269</jats:related-article> </jats:p>

<jats:title>Thinning a ferroelectric makes it better</jats:title> <jats:p> As a ferroelectric material becomes thinner, the temperature below which it develops its permanent electrical polarization usually decreases. Chang <jats:italic>et al.</jats:italic> fabricated high-quality thin films of SnTe that, in contrast to this conventional wisdom, had a considerably higher transition temperature than that of the material in bulk (see the Perspective by Kooi and Noheda). This was true even for single-unit cell films, whereas only slightly thicker films became ferroelectric above room temperature. This finding may enable the miniaturization of ferroelectric devices. </jats:p> <jats:p> <jats:italic>Science</jats:italic> , this issue p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6296" page="274" related-article-type="in-this-issue" vol="353" xlink:href="10.1126/science.aad8609">274</jats:related-article> ; see also p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6296" page="221" related-article-type="in-this-issue" vol="353" xlink:href="10.1126/science.aaf9081">221</jats:related-article> </jats:p>

<jats:title>A light approach to C-N bond formation</jats:title> <jats:p> The need to form C-N bonds arises frequently in drug discovery research. One versatile approach involves the attachment of the C and N fragments to a Pd catalyst. This approach needs a bulky ligand to “crowd” the fragments together off the metal center. Corcoran <jats:italic>et al.</jats:italic> present a complementary approach that uses Ni in place of Pd. Instead of the bulky ligand, they used a light-activated cocatalyst that strips an electron from the Ni to accelerate the bond formation. A screen involving elaborately substituted reagents confirmed the utility of this approach in cases that challenge the traditional Pd coupling. </jats:p> <jats:p> <jats:italic>Science</jats:italic> , this issue p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="6296" page="279" related-article-type="in-this-issue" vol="353" xlink:href="10.1126/science.aag0209">279</jats:related-article> </jats:p>