Since the discovery of graphene in 2004, scientists have found that this honeycomb-like sheet of carbon atoms is not just the thinnest material known in the world, but also incredibly light and flexible, hundreds of times stronger than steel, and more electrically conductive than copper.
It turned out recently that a sandwich of two graphene layers can be tuned, by twisting the angle between two sheets, to behave at two electrical extremes: as an insulator, in which electrons are completely blocked from flowing; and as a superconductor, in which electrical current can stream through without resistance. More about it, here!
The effects of rotation in twisted bilayer graphene. a, When a graphene bilayer is twisted so that the top sheet is rotated out of alignment with the lower sheet, the unit cell (the smallest repeating unit of the material’s 2D lattice) becomes enlarged. For large rotations, the electronic band structures of the two graphene sheets are also rotated out of alignment (not shown). b, For small rotation angles, a ‘moiré’ pattern is produced in which the local stacking arrangement varies periodically. Cao et al.1,2 have observed that, for rotation angles of less than 1.05°, regions in which the atoms are directly above each other (the lighter regions in the pattern) form narrow electron energy bands, in which electron ‘correlation’ effects are enhanced. This results in the generation of a non-conducting state2 (a Mott insulator), which can be converted into a superconducting state1 if charge carriers are added to the graphene system. [Nature, News and Views, E.J.Mele, 05 MARCH 2018]
- Cao, Y. et al. Nature http://dx.doi.org/10.1038/nature26160 (2018).
- Cao, Y. et al. Nature http://dx.doi.org/10.1038/nature26154 (2018).
The United Nations have proclaimed February 11 the International Day of Women and Girls in Science aiming to ensure full and equal access to and participation in science for women and girls.
Events in Trieste
To celebrate the International Women and Girls in Science Day 2018 and to join forces to build an inclusive scientific community, ICTP, Organization for Women in Science for the Developing World (OWSD) and SISSA are organizing two events scheduled on 7 and 9 February 2018.
At Antico Caffé San Marco on 7 February 2O18 a discussion aperitivo will take place starting from 6 pm . Following some short presentations from representatives of Trieste scientific institutions, the floor will be open for a discussion of the current status quo, the specific challenges facing members of our community, and specific events and strategies for moving forward. The second event will take place on 9 February 2018 at ICTP from 10.00 to 11.00. In that occasion, a group of female researchers from ICTP and SISSA will give a 5 minute talk to present to high school students their work as scientists.
Also the Science Centre – Immaginario Scientifico of Trieste is going to celebrate on Sunday Feb. 11th. All-female staff will guide inside the museum (10 am – 6 pm). Reduce fee for women. No reservation needed.
Actividades en Madrid y toda España
En Madrid y en toda España ya está en marcha la organización de actividades para conmemorar el Día Internacional de la Mujer y la Niña en Ciencia en Febrero de 2018.
Charlas, talleres, concursos, exposiciones y mesas redondas llenarán los museos, planetarios, centros culturales, las universidades y hasta el bar de la esquina.
Actividades 2018 (Toda España)
Muchas gracias a todas las mujeres (y todos los hombres también!) de la organización de ese 11/02 2018 y en particular gracias a mi queridas colegas del ICMM que el año pasado han puesto en marcha todo eso! Mucha suerte!
Mas informaciones sobre Mujer y Ciencia
Excitons are pairs of electrons and holes inside a solid material that together behave like a single particle. It has long been suspected that when many such excitons exist in the same piece of matter, they can form a Bose-Einstein condensate. However, actually proving that Bose-Einstein condensation of excitons occurs in any real material has been a challenge for physicists for decades. Experimental evidence of such a state has been found!
A comment about the discovery: Spontaneous Bose-Einstein condensation of excitons
The scientific article: Signatures of exciton condensation in a transition metal dichalcogenide
Trieste was selected to host the EuroScience Open Forum, the most important European event dedicated to science, technology, society and policy. The event will take place from 4 to 10 July 2020. TRIESTE ESOF 2020
The old harbor area of Trieste
A postdoctoral position is available at the Condensed matter group of SISSA/ISAS (International School of Advanced Studies), in the group of of Massimo Capone, starting in Summer/Fall 2017.
The research activity is focused on strongly correlated materials close to Mott transitions using many-body approaches like Dynamical Mean-Field Theory, Gutzwiller approximation and slave-particle approaches in combination with Density-Functional Theory.
These approaches will be applied to explore the properties of iron-based superconductors, iridates and transition-metal oxides, but also fullerides and other organic materials, exploring the relation between many-body physics and functional properties of the materials. We will also explore non-equilibrium dynamics of these systems in close collaboration with experimental groups.
An experience in the above mentioned approaches is highly desirable. Candidates with some experience in the combined use of DFT and many-body approaches are ideal for the position.
The position is for two years with a possible one-year renewal.
Interested applicants should send a CV, list of publications, research interests, and the names of two references to email@example.com.
Let conclude our 2016 with 10 amazing stories of science selected by David Grimm, online editor of Science: Top 10 fovorite science news stories of 2016
“This year’s Laureates opened the door on an unknown world where matter exists in strange states. The Nobel Prize in Physics 2016 is awarded with one half to David J. Thouless, University of Washington, Seattle, and the other half to F. Duncan M. Haldane, Princeton University, and J. Michael Kosterlitz, Brown University, Providence. Their discoveries have brought about breakthroughs in the theoretical understanding of matter’s mysteries and created new perspectives on the development of innovative materials.
The three Laureates’ use of topological concepts in physics was decisive for their discoveries. Topology is a branch of mathematics that describes properties that only change step-wise. Using topology as a tool, they were able to astound the experts. ”
Read more about this year’s prize
Popular Science Background