Yann Pouillon

Universidad del País Vasco / Euskal Herriko Unibertsitatea | UPV/EHU · Departamento de Física de Materiales

First-principles electronic structure calculations are now accessible to a very large community of users across many disciplines, thanks to many successful software packages, some of which are described in this special issue. The traditional coding paradigm for such packages is monolithic, i.e., regardless of how modular its internal structure may...

A review of the present status, recent enhancements, and applicability of the SIESTA program is presented. Since its debut in the mid-nineties, SIESTA's flexibility, efficiency and free distribution has given advanced materials simulation capabilities to many groups worldwide. The core methodological scheme of SIESTA combines finite-support pseudo-...

A review of the present status, recent enhancements, and applicability of the Siesta program is presented. Since its debut in the mid-1990s, Siesta’s flexibility, efficiency, and free distribution have given advanced materials simulation capabilities to many groups worldwide. The core methodological scheme of Siesta combines finite-support pseudo-a...

First-principles electronic structure calculations are very widely used thanks to the many successful software packages available. Their traditional coding paradigm is monolithic, i.e., regardless of how modular its internal structure may be, the code is built independently from others, from the compiler up, with the exception of linear-algebra and...

Abinit is a material- and nanostructure-oriented package that implements density-functional theory (DFT) and many-body perturbation theory (MBPT) to find, from first principles, numerous properties including total energy, electronic structure, vibrational and thermodynamic properties, different dielectric and non-linear optical properties, and rela...

Norm-conserving pseudopotentials are used by a significant number of electronic-structure packages, but the practical differences among codes in the handling of the associated data hinder their interoperability and make it difficult to compare their results. At the same time, existing formats lack provenance data, which makes it difficult to track...

We present libvdwxc, a general library for evaluating the energy and potential for the family of vdW-DF exchange--correlation functionals. libvdwxc provides an efficient implementation of the vdW-DF method and can be interfaced with various general-purpose DFT codes. Currently, the GPAW and Octopus codes implement interfaces to libvdwxc. The presen...

We describe the functionalization of SWNTs enriched in (6,5) chirality with electron donating macrocycles to yield rotaxane-type mechanically interlocked carbon nanotubes (MINTs). Investigations by means of electron microscopy and control experiments corroborated the interlocked nature of the MINTs. A comprehensive characterization of the MINTs thr...

ABINIT is a package whose main program allows one to find the total energy, charge density, electronic structure and many other properties of systems made of electrons and nuclei, (molecules and periodic solids) within Density Functional Theory (DFT), Many-Body Perturbation Theory (GW approximation and Bethe–Salpeter equation) and Dynamical Mean Fi...

Many applications of carbon nanotubes require their chemical functionalization. Both covalent and supramolecular approaches have been extensively investigated. A less trodden path is the combination of both covalent and noncovalent chemistries, where the formation of covalent bonds triggers a particularly stable noncovalent interaction with the nan...

Extensive research has been devoted to the chemical manipulation of carbon nanotubes. The attachment of molecular fragments through covalent-bond formation produces kinetically stable products, but implies the saturation of some of the CC double bonds of the nanotubes. Supramolecular modification maintains the structure of the SWNTs but yields labi...

Extensive research has been devoted to the chemical manipulation of carbon nanotubes. The attachment of molecular fragments through covalent-bond formation produces kinetically stable products, but implies the saturation of some of the CC double bonds of the nanotubes. Supramolecular modification maintains the structure of the SWNTs but yields lab...

Designing nanoscale devices, such as gas sensors and thermal dissipators, is challenging at multiple levels. Exploring their properties through combined experimental and theoretical collaborations is a valuable approach that expands the understanding of their peculiarities and allow for the optimization of the design process. In order to select the...

The method to calculate van der Waals interactions based on maximally localized Wannier functions (MLWFs), proposed by Silvestrelli [Phys. Rev. Lett. 100 (2008) 053002], has been implemented within the ab initio DFT program ABINIT. In addition to a brief review of the theoretical background behind this methodology, we present the details of the imp...

The European Theoretical Spectroscopy Facility (ETSF) is a distributed knowledge network that gives researchers access to state-of-the-art computer simulations for electronic excited states in matter. Focusing on the fundamental knowledge of matter at the quantum-mechanical level, ETSF seeks to transfer this understanding to the future design of te...

We review the recent implementationootnotetextC. Espejo et al. Computer Phys. Comm. In press (2011), doi:10.1016/j.cpc.2011.11.003 of the method to evaluate van der Waals (vdW) interactions based on maximally localized Wannier functionsootnotetextP. L. Silvestrelli. Phys. Rev. B., 100, 053002 (2008)^,ootnotetextP. L. Silvestrelli. J. Phys. Chem. A....

When it comes to developing scientific software, the most prominent trait of scientists gathered around a specific project is their varied approach to computer science: they're not employed as developers, and they're often self-taught programmers. This article discusses that larger efforts require an organized, structured community to keep pace wit...

Drop-cast thin films of multi-walled carbon nanotubes are used as gas sensors in a four-probe measurement setup. The novelty of the approach is that the sensor information is extracted from the noise of the dc resistance data using Fluctuation Enhanced Sensing (FES). We investigate the effects of measurement duration, gate voltage and frequency win...

ABINIT [http://www.abinit.org] allows one to study, from first-principles, systems made of electrons and nuclei (e.g. periodic solids, molecules, nanostructures, etc.), on the basis of Density-Functional Theory (DFT) and Many-Body Perturbation Theory. Beyond the computation of the total energy, charge density and electronic structure of such system...

Nowadays gas detection in the ppm and sub-ppm domain is essential in terms of environmental protection as well as reducing sanitary risks. However, detecting systems to perform these measurements (e.g., gas chromatographs) are expensive and take up too much space, thus their use is not likely to become wide-spread. Small, cheap and easily mountable...

We present a library of routines whose main goal is to read and write exchangeable files (NetCDF file format) storing electronic structure and crystallographic information. It is based on the specification agreed inside the European Theoretical Spectroscopy Facility (ETSF). Accordingly, this library is nicknamed ETSF_IO. The purpose of this article...

In order to allow different software applications, in constant evolution, to interact and exchange data, flexible file formats are needed. A file format specification for different types of content has been elaborated to allow communication of data for the software developed within the European Network of Excellence "NANOQUANTA", focusing on first-...

A brief introduction to the ABINIT software package is given. Available under a free software license, it allows to compute directly a large set of properties useful for solid state studies, including structural and elastic properties, prediction of phase (meta)stability or instability, specific heat and free energy, spectroscopic and vibrational p...

The bonding between copper and oxygen atoms and its evolution with size has motivated extensive photoelectron spectroscopy measurements (see H. Wu, S. Desai, L.-S. Wang, J. Phys. Chem. A, 101 (1997) 2103–2777). Despite the small sizes involved in the experimental work carried out so far, the structure of the isomers is far from being elucidated. To...

In both clusters and disordered systems the determination of structural properties often relies on qualitative interpretations of experimental data. First-principles molecular dynamics provides a reliable atomic-scale tool to optimize geometries and follow the dynamical evolution at different temperatures. We present three examples of application o...

We determine the equilibrium structures of CuO4 and CuO5 clusters within the framework of density functional theory and a plane-wave approach. Our calculations go beyond qualitative structural assignments proposed to interpret photoelectron spectroscopy measurements. We found that the lowest energy structures for CuO4 are based on Cu(O2) units, iso...

Rapporteurs : Pr H. Dreyssé, Pr X. Gonze, Pr P. Gressier / Examinateur : Dr M.M. Rohmer / Invité : Dr M. Drillon

Structural minima of neutral and negatively charged CuO6 clusters have been investigated within density functional theory and a plane-wave approach. Among the lower energy structures, three isomers made of CuO2 complexes and two isomers featuring a double ozonide Cu(O3) unit lie within a few hundredths of eV. Isomers containing CuOOO chains are hig...

Copper hydroxonitrate has been investigated within density functional theory and a plane-wave approach. In order to elucidate the topology of the spin density distribution and the microscopic origins of the antiferromagnetic character of this compound, systems with an equal number of unit cells differently oriented in space have been considered. Pa...

IntroductionPhenomenological Description of Exchange Coupling: the Heisenberg HamiltonianQualitative Models of the Exchange Coupling Mechanism Orthogonal Magnetic OrbitalsNatural Magnetic OrbitalsQuantitative Evaluation of Exchange Coupling Constants Perturbative and Variational Calculations of State Energy DifferencesAb initio Calculations of Stat...

Structural and electronic properties of neutral and anionic CuO2 molecules are investigated within density functional theory. The lowest energy structures are the bent CuOO and the linear OCuO−. Consideration of temperature effects via first-principles molecular dynamics simulations allows to conclude that two CuO2− isomers (bent CuOO− and CuO2− si...

By using first-principles calculations within density functional theory via the local density approximation (LDA) and the generalized-gradient approximation (GGA) of Perdew and Wang for exchange and correlation, we calculate the equilibrium structures of CuO2 and CuO- 2 clusters. In the case of CuO2, three isomers (OCuO linear and two CuO2 complexe...

In both clusters and disordered systems the determination of structural properties often relies on qualitative interpretations of experimental data. First-principles molecular dynamics provides a reliable atomic-scale tool to optimize geometries and follow the dynamical evolution at different temperatures. We present three examples of application o...

ABINIT is a Fortran 90 free software application that allows the atomic-scale simulation of properties of matter, thanks to Density Functional Theory and Many-Body Perturbation Theory. It is used by more than thousand individuals, who enjoy the wide spectrum of properties that ABINIT allows to compute easily. Several dozen developers contribute to...