Welcome to CMAST Lab
Materials for new technologies

Ab-initio characterization of graphene on amorphous copper:
Graphene Graphene production process can be optiized by accurate ab-initio characterization of the interface betwen graphene and the substrate. Amorphous copper is experimentally indicated as one of the most interesting substrate. Formation energies, charge transfer, electronic band structure and induced strains are computed and interpreted.
  • Dr. Francesco Buonocore, ENEA
Molecular Dynamics simulations of Cu64Zr36 metallic glasses:
CuZr Cu64Zr36 metallic glasses are characterized by extensive Molecular Dynamics simulations. An amorphous sample is produced by quenching from the melt. The pair correlation functions of the liquid and the glass are calculated and compared for different temperatures. The topological short-range order is analyzed by the Voronoi tessellation method. The most prominent atomic arrangements in the glass are Cu-centered icosahedra. Subsequently, the sample was uniaxially compressed to investigate the mechanical deformation in metallic glasses. A stress-strain curve was measured, which shows stress drops in the plastic regime that might stem from shear-transformation zones. However, larger systems have to be investigated to observe shear-band formation, which is known to be present in the real material.
  • Prof. Bernd Schonfeld, dr. Jerome Zemp, Univ. of Zurich
Ab-initio Molecular Dynamics simulations of amorphous germanium:
We employ ab-initio molecular dynamics simulations to study the atomic structure of amorphous germanium. The preparation of amorphous Ge is performed by cooling from the liquid phase. Structural and thermal properties of the amorphous phase are calculated in good agreement with experimental data. This is a mandatory step for starting a complete characterization of the pressure effects on the amorphous germanium.
  • Prof. Andrea Di Cicco, dr. Giorgio Mancini, Univ. of Camerino
Ab-initio characterization of Zr43O86 clusters:
ZrO Ab-initio molecular dynamics simulations are used to optimize the atomic configuration of zirconium oxide clusters. Surface properties and reactivity are computed and compared with recent experimental results. The good agreement with experiments allows to extend this approach to greater and different clusters.
  • dr. Roberto Grena, ENEA

Remote control of a Transmission Electron Microscopy (TEM)
A Transmission Electron Microscopy is installed in the ENEA Research Centre of Brindisi equipped with all the instrumentation for remote control and data acquisition. An original and customized software interface allows the microscope to be a resource of the ENEA Grid environment. In this way any ENEA Grid user, with a PC equipped with a simple interface, can use from everywhere the microscope.
  • dr. Marco Vittori Antisari, ENEA
Crystalline and liquid Si3N4 characterization by first-principles molecular dynamics simulations:
Ni3Si4 Silicon nitride (Si3N4) has a wide range of engineering applications where its mechanical and electronic properties can be effectively exploited. In particular, in the microelectronics field, the amorphous silicon nitride films are used as charge storage layer in metal-alumina-nitride-oxide nonvolatile memory devices. Atomic structure of amorphous silicon nitride is characterized by high concentration of traps that control the electric behavior of the final device by the trapping-de-trapping mechanism of the electrical charge occurring in its traps. In order to have a deep understanding of the material properties and, in particular, the nature of the electrical active traps a detailed numerical characterization of the crystalline and liquid phases is mandatory. For these reasons first-principles molecular dynamics simulations are extensively employed to simulate the crystalline Si3N4 in its crystalline and liquid phases. Good agreement with experimental results is obtained in terms of density and formation enthalpy. Detailed characterization of crystalline Si3N4 electronic properties is performed in terms of band structure and band gap. Extensive first-principles molecular dynamics simulations are performed to obtain a reliable liquid sample. Detailed characterization of the atomic structure is achieved in terms of radial distribution functions and total structure factor.
  • dr. Aurelio Mauri, MICRON
  • dr. Massimo Celino, ENEA
Materials with high ionic conducibility:
Water Materials of the class AX2 (A=Si, Ge; X= O, Se, S) are studied in their liquid and amorphous phase in view of their application for sensors and batteries. Structural and electronic characterization are performed by using molecular dynamics code based on ab-initio scheme. In the case of SiSe2, the calculated structure factor is in very good agreement with experiments, as well as the number of corner- and edge-sharing tetrahedra. By focusing on the sequences of Si atoms linked via intra- and intertetrahedral bonds, we identify the predominant structural motifs. The sequences involving both corner- and edge-sharing connections are significantly more frequent than those formed exclusively by edge-shared Si atoms. Our results clarify a longstanding controversy on the structure of this prototypical disordered network-forming material.
  • dr. Massimo Celino, ENEA
Undercooling metals:
We elucidate the role played by defective icosahedra on the stability of undercooled copper by using molecular-dynamics simulations. Our approach is substantiated by the level of agreement with experiments on a variety of structural properties. We show that not only perfect but also defective icosahedra, embedded in a disordered matrix, lower the local cohesive energy. This has the effect of stabilizing the liquid structure against crystallization. Our work rationalizes experimental findings by identifying the nature of those icosahedral subunits that contribute to the stability of the undercooled liquid.
  • dr. Massimo Celino, ENEA
Ab-initio calculations of electronic properties of 2-dimensional materials:
Graphene/Graphane Possible applications of graphene in electronic nanodevices make it desirable to render graphene semiconducting. Chemical functionalization seems to be the natural pathway to reach this goal. Experimentally hydrogenation of graphene has been recently achieved giving rise to the so called 'graphane'. DFT-GGA ab-initio calculations of graphane are performed to to characterize the metal-insulator transition driven by the hydrogen adsorption.
  • prof. Olivia Pulci, Univ. Tor Vergata, Roma

Catalysis:
New elements are selected and studied for catalysis processes. Catalysis plays a fundamental role for the production of materials and molecules but it needs to be a safe and no polluntant process.
  • prof. Luigi Cavallo, Univ. Salerno
Structural materials:
A first-principles pseudopotential method is used to investigate the structural, elastic and phonon properties of ScAs and ScSb in their ambient B1(NaCl) and in high pressure B2 (CsCl) phases. The calculated lattice constants, static bulk modulus, first order pressure derivative of the bulk modulus and the elastic constants are reported in B1 and B2 structures and compared with available experimental and other theoretical results. The phonon properties of two compounds are compared among themselves which reveal that these compounds are predominantly metallic, due to degeneracy of optical frequencies at zone centre. At high pressure, near B1 to B2 transition, the LA mode at X-point softens leading to structural instability.
  • dr. Bipul Rakshit, Univ. Barkatullah
  • prof. S.P. Sanyal, Univ. Barkatullah
Waste management: supercritical water
Water Water at supercritical conditions (obtained for temperatures higher than 648 K) shows a broad spectrum of chemical physical properties of technological interests that could be used for example to produce a new class of solvents. In fact, by simply tuning the external pressure it is possible to tune some properties such as, for example, the dielectric constant. At high pressures, the dielectric constant is similar to that of ambient water (a highly polar liquid), but at low pressures, it is close to zero, as for a non-polar liquid. At molecular level it has been seen that the water tends to form local clusters, causing the density to be heterogeneous. The main goal of this project is to understand the molecular details which rule the macroscopic behaviour. To this end, characterization of hydrogen bond dynamics and of rotational relaxations are performed by ab-initio calculations with the CP2K code.
  • dr. Marco Masia, University of Sassari