The ABC of trilayer graphene

Graphene TimeThe “wonder material” graphene is an active focus of research at the Center for Nanotechnology Innovation, IIT@NEST. Recently, trilayer graphene has attracted wide attention owing to its stacking and electric-field-dependent electronic properties. However, a direct and well-resolved experimental visualization of its band structure was never reported before today.

Our work, entitled “Revealing the electronic band structure of trilayer graphene on SiC: An angle-resolved photoemission study,” fills this gap by presenting high-resolution angle-resolved photoemission spectroscopy (ARPES) data which reveal for the first time the electronic band structure of trilayer graphene obtained on silicon carbide via hydrogen intercalation. The electronic bands of both stable forms of trilayer graphene – i.e., Bernal (ABA) and rhombohedral (ABC), differing for the vertical stacking of the individual carbon layers – were observed with a remarkable agreement with theoretical calculations from tight-binding models.

Notably, our study shows that on SiC substrates the occurrence of ABC-stacked trilayer is significantly higher than in natural bulk graphite. This still-to-be-explained finding might open an unexpected route towards the fabrication of a new class of gap-tunable devices because the ABC-stacked trilayer graphene is the most appealing form of trilayer for electronic applications, thanks to its tunable band-gap, but it is also the most uncommon in natural graphite.

The study was performed in collaboration with scientists from the Max-Planck Institute of Stuttgart, the Istituto Nanoscienze-CNR and Scuola Normale Superiore, the MAX-lab of Lund, the University of South Carolina, the Laboratoire des Matériaux et du Génie Physique of Grenoble and the University of Texas at Austin.


For more information: Graphene Time




State of art electron crystallography at IIT@NEST

Microscopy And Analysis

A new nanocrystallography facility has recently been set up at the Center for Nanotechnology Innovation, IIT@NEST. Our TEM is now equipped with a special device, which allows determining the structure of unknown, nanometer-sized samples: it is like having a single crystal diffractometer for nanocrystalline grains.
The method, implemented at IIT@NEST for the first time on an energy filtered TEM, consists in collecting electron diffraction patterns in precession mode on nanocrystals as small as 100 nm. The precession electron diffraction is combined with the rotation of the sample allowing the reconstruction of a large portion of the reciprocal space of the crystal. Additionally, for the first time ever the electron diffraction tomography data have been recorded in energy filtered mode, making the diffracted peaks much sharper and strongly reducing the diffuse inelastic background. The article published in Microscopy and Analysis stems from the combined efforts of the CNI, the Nanomegas company and the Universities of Patras and Athens in Greece.  
For more information: microscopy and analysis


A novel imaging method developed at NEST Laboratory and Center fo Nanotechnology Innovation of IIT@NEST

Pnas figureAn important area of research at Center for Nanotechnology Innovation@NEST, Istituto Italiano di Tecnologia in Pisa is the development of novel imaging methods. The classical Fluorescence Correlation Spectroscopy approach and its variants were recently introduced to study protein diffusion, aggregation state, and interactions in the context of a living cell/sample and in presence of many molecules. In July 2013 researchers of the CNI presented a new method to study the spatial distribution and dynamics of single proteins in live, unperturbed cell membranes. The method is based on spatio-temporal image fluctuation analysis. Notably, in this approach the authors did not extract the trajectory of each particle, but calculated population averages of particle distribution and dynamics. By this approach they extracted the actual protein ‘diffusion law’ directly in the form of a mean square displacement vs time-delay plot (iMSD), with no need for interpretative models.For the first time the actual diffusion law of a fluorescently labeled protein on the plasma membrane was reconstructed over a 4-order-of-magnitude timescale. It is noteworthy that, unlike classical single particle tracking, this fluctuation-based method works well at high molecular densities, low signal-to-background ratios, and high counting noise levels. This combination of properties allows “single-molecule” experiments in presence of many similarly labeled molecules diffusing at the same time.This approach is of general interest to the wide public of biologists, physicists, and chemists studying membrane molecular transport in the cell environment.The article, published on the international journal Proceedings of the National Academy of Science, “Fast spatiotemporal correlation spectroscopy to determine protein lateral diffusion laws in live cell membranes" ,reports on an activity carried out by researchers of the IIT in Pisa, in collaboration with the Laboratory for Fluorescence Dynamics, University of California, Irvine.

For more information : www.Pnas.org

Marco Travagliati:Poster Award@ELA2013 Winner

Marco Travagliati Winner @ELA2013
Marco Travagliati and Richard Shilton
European Lab Automation congress, held this year in Hamburg, is Europe's largest event dedicated to the automation of life science processes both in companies and academia. In this context micro and nanofluidics have recently drawn particular attention and one the five streams of the conference was dedicated to this topic. Fluid manipulation at the pico and nanoliter scale is an exponentially growing, highly interdisciplinary field involving physicist, engineers, chemists and biologist. Microfluidics not only allows a high degree of parallelization of lab operations, but also offers outstanding control on the through-put compared to standard batch preparations. The leaders in this research area presented seminal lectures of the latest advancements in lab-on-a-chip technologies and applications. In this showcase, we presented a poster for the automation of surface acoustic wave microfluidics, a patented IIT technology published last year in Lab on a chip. By exploiting the resonant properties of phononic crystals, we realized the first scheme for integrated automatic interaction-free routing of fluids on surface acoustic wave lab-on-a-chip devices. Moreover, this technology can form the heart of on-chip logic gates and sequencers based on instantaneous distribution of nano and picoliter volumes of fluids.


For more information : Eposters.net

The new drug delivery system of the NEST Laboratory and the Center for Nanotechnology Innovation of IIT@NEST

Small Nano MicroA group of researchers of the NEST laboratory and CNI@NEST was awarded of the prestigious frontispiece of SMALL for the developing of a new drug delivery and controlled release system of active agents based on gold nanostructures. This innovative nano-material exploits a multi-photon effect observed for the first time at NEST, which makes possible the release of biomolecules with common continuous low-power lasers at wavelengths close to the "optical window" in the visible range. This pioneering study provides an important achievement towards the development of a new class of promising anticancer and therapeutic agents. For more details click on the image.

For more information : Small Nano Micro

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