Hooray! In a publication in ACS Nano Letters, André Saraiva and Belita Koiller demonstrate how to identify a pair of impurities in silicon, in analogy to the H2 molecule. The peculiarities of the Si conduction electrons permit to electrically contact and pass a current through this molecule. The result — extremely different from Ohm’s law, makes possible to identify parameters of this molecule, such as the separation between impurities.
Hooray!!! This issue of Environmental Science and Technology publishes an article by Rodrigo Capaz and our group’s collaborators from INMETRO. In this study, they take a step back from the usual interests of the group to discuss Terra Preta de Índio (Amazonian Dark Earths) a system of interest for soil and climate sciences.
The soil of the amazon forest is not naturally adequate for planting. It may be enriched, though, through ancient techniques which generate black carbon. Black carbon is also an interesting carbon sink — CO2 absorbed from the atmosphere remains biologically inactive (or recalcitrant) in its form. This is recognized by the Kyoto protocol as a form of offsetting the carbon footprint.
In this work, Rodrigo and colleagues analysed from the quantum chemistry point of view the molecular models for these large carbon molecules and the interaction between carbon, oxygen and calcium.
Hooray!!! Today’s cover at the Physical Review Letters electronic edition highlights the letter “Single-Shot Readout and Relaxation of Singlet and Triplet States in Exchange-Coupled P31 Electron Spins in Silicon”, in co-authorship with André Saraiva.
A pair of isolated donors had its quantum state measured instantly through a method developed by the experimental group at University of New South Wales led by Andrea Morello and Andrew Dzurak. The method detects tunneling events from the donors to a neighboring SET (single electron transistor).These measurements show that there is still a lot to learn before we are able to harness electronic spins for quantum computation.
In particular, the incompatibility between the valley structure (composition of conduction band minima) at the donors and at the SET led to a more complex scenario than anticipated. Not only the lowest singlet and triplet participate in the quantum evolution, but also the excited triplet that is compatible to the SET quantum state.
The article shares the PRL cover with an important result obtained in particle physics: the generation of a top quark through a rare channel that does not involve the creation of an antiparticle.
http://journals.aps.org/prl/abstract/10.1103/PhysRevLett.112.236801
Rodrigo Capaz will now be part of the Advisory Committee (Comitê de Assessoramento) for Physics and Astronomy at CNPq. As a member, he will counsel this funding agency about scientific proposals and grant allocation.
Read more about this committee here: http://www.cnpq.br/web/guest/membros-dos-comites
Hooray!!! This issue of the PNAS contains an article co-authored by Rodrigo Capaz: “Systematic determination of absolute absorption cross-section of individual carbon nanotubes”.
In this contribution, they develop a technique to determine the cross section for light absorption of a single carbon nanotube at a time! Comparing with theory, they were able to understand how the absorption spectra relate to the exciton oscillator strength and lifetime, as well as the chirality of the nanotube under analysis.
http://www.pnas.org/content/111/21/7564.abstract
Hooray!!! Journal of Physics: Condensed Matter published last week the article “Magnetic response of zigzag nanoribbons under electric fields”, by Francisco Culchac and Rodrigo Capaz. Francisco is a former post-doc of Rodrigo’s and currently a collaborator and friend of the group working at INMETRO. Congratulations, Francisco!
Read the article below and send us a message if you have questions or comments. We will be happy to forward it to Francisco.
Here is the article for subscribers:
Hooray!!! This year’s ENFMC — the Brazilian condensed matter physics yearly meeting — is taking place at beautiful Costa do Sauipe, Bahia. And NAMOR’s proud post-doc Alejandra Baena Vasquez got the prize for best poster at this Tuesday’s session with her work “Electric field control of an artificial H2+ molecule in Silicon”! Congratulations, Alejandra!
You can learn more about her work reading the abstract below or sending us a message, which we will be glad to transmit to her.
http://www.sbf1.sbfisica.org.br/eventos/enfmc/xxxvii/sys/resumos/R1025-2.pdf
Hooray! Physical Review B published today “Splitting valleys in Si/SiO2: Identification and control of interface states” — the master’s research project of Amintor Dusko, supervised by Belita Koiller. And it was selected as an “Editors’ Suggestion” too! Congratulations, Amintor!
You can learn more about his work reading the paper below or sending us a message, which we will be glad to transmit to him.
Subscribers only:
http://journals.aps.org/prb/abstract/10.1103/PhysRevB.89.205307
Freely available at:
http://arxiv.org/abs/1310.6878
