Research

September 2010
A paper co-authored by G. Kopidakis is published in EPL as an editor's choice.
May 2010
A figure from our paper is use on the front cover of the May 2010 issue of Physica Status Solidi. See also the table of contents.
Cover of PSS C featuring a figure from our paper
May 2010
A paper by N. V. Galanis, I. N. Remediakis and G. Kopidakis is published in Physica Status Solidi.
June 2009
A paper by I. N. Remediakis is published in a special issue of Surface Science dedicated to Gerhard Ertl.
April 2009
A paper by G. Kopidakis is published in Europhysics Letters.
Jan. 2009
A book from the IUTAM bookseries contains a chapter co-authored by IR and GK (also here).
Oct 3, 2008
Our latest paper is published in the October issue of Acta Materialia.
February 29, 2008
A paper by Prof. Georgios Kopidakis was published in Physical Review Letters. A copy can be found here.

Methodology

Atomistic Simulations and Electronic Structure Theory

Computer-aided Design of new Materials

Nano is different

Jewel from Malia, Greece reaction path for CO oxidation on a gold nanoparticle

Gold cannot be oxidized, as can be seen from the rust-free, 4000-year old minoan pendant on the left . Gold nanoparticles, however, react readily with any small molecule, and are superb catalysts. DFT calculations (right) reveal the mechanism of an exemplar reaction, CO oxidation.

Virtual nanocatalyst for ammonia synthesis

observed and theoretical shapes of Ru particles

(A) TEM image of a supported Ru particle with a step. (B) Particle size distribution function obtained from the TEM experiments. (C) Typical calculated Ru particle, with an average diameter of 2.9 nm. Atoms that belong to active B5 sites are colored red. (D) Density of active sites as a function of particle diameter as calculated by analyzing the atomistic Wulff construction.

Amorphous and Nanocomposite Carbon

Properties of a-C from Mathioudakis et al., PRB 2004 Diamond/a-C nanocomposite from Fyta et al., PRL 2006

Amorphous Carbon (a-C) is a material with unique mechanical properties. It is fully biocompatible and has promising optoelectronic properties. The properties can be fine-tuned By inducing diamond or graphite-like nanocrystals of various sizes and at various volume fractions. We have performed numerous studies of a-C and other carbon-based materials in close collaboration with Prof. Pantelis C. Kelires from the Cyprus University of Technology.

Universal bulk modulus versus density curve for carbon-based materials

bulk modulus of nanocomposite carbon as a function of density

Although anisotropic at the atomistic level, carbon-based are highly isotropic at the meso-scale. For example, their bulk modulus is a unique function of density. The image above shows results for diamond, amorphous carbon, nanocomposite carbon and amorphous diamond from a tight-binding calculation. At the limits of low and high densities, the materials behave as jellium metals and molecular crystals, respectively.

Reverse Hall-Petch effect in Ultra-Nanocrystalline Diamond

ball-and stick model of UNCD youngs modulus, shear modulus and hardness of uncd as a function of grain size

Model of nanocrystalline diamond (left) and dependence of elastic moduli and hardness on the average grain size.