Daresbury Laboratory, UK, 13-17 May 2019

Organisers:

Daresbury: Leon Petit, Jerome Jackson, Martin Lüders

King’s College London: Mark van Schilfgaarde, Dimitar Pashov

The third Questaal school concentrated on qsGW and DMFT using the code’s new interface to the TRIQS library.  A series of tutorials enabled the 31 participants (mostly post-doctoral researchers and lecturers) to setup and run calculations starting from density functional theory and working up to GW, qsGW, LDA + Bethe Salpeter (BSE), or the inclusion of ladder diagrams in W: qsGW^BSE, and DMFT.  The participants were encouraged to experiment with a diverse range of materials, including itinerant magnets, f-electron systems, simple semiconductors and strongly correlated insulators.

In addition to the new TRIQS DMFT capability, the school also showcased recent developments in extending the GW self-energy by including phonon contributions and the first results of the new “Jigsaw Puzzle Orbital” basis, which is a full-potential analogue of the LMTO screening transformation which is short ranged and compact while still very precise. Continue reading 3rd Daresbury QUESTAAL School →

Workshop on Crystal Structure Prediction: Exploring the Mendeleev Table as a Palette to Design New Materials

ICTP, Trieste, 14-18 January 2019

Final report

Thanks to enormous progress in computing power and in algorithm development, we are now closer to being able to predict the crystal structure of any material from the simple knowledge of its composition. This is the first necessary step for predicting in silico the property of a material, and planning modifications that could improve these properties. A critical discussion of the algorithms developed in the last years for the “in silico” prediction of crystal structures was the main theme of a workshop that took place at the Abdus Salam International Centre for Theoretical Physics (ICTP), in Trieste, Italy,  from 14 to 18 January 2019. The event, titled “Workshop on Crystal Structure Prediction: Exploring the Mendeleev Table as a Palette to Design New Materials”, focused in particular on approaches based on molecular modeling and was an opportunity to celebrate 2019 as the International Year of the Periodic Table, since crystal structure prediction is rooted in a deep knowledge of the properties of the atoms, and, in turn, numerous discoveries made with the help of crystal structure prediction, reveal new (often completely unexpected) sides of the behavior of the atoms. The Workshop was directed by the A. Laio, G. Desiraju, A. Oganov, and S. Scandolo. It was divided in two parts: the first three days were dedicated to an in-depth and critical discussion of the methods, with talks given by world experts in the field. The last two days were devoted to “hands-on” computer labs were the younger participants were given the opportunity to learn how to use the most advanced codes for crystal structure prediction, including the “Universal Structure Predictor: Evolutionary Xtallography” (USPEX) and the “Ab initio Random Structure Searching” (AIRSS). Continue reading Report on Workshop on Crystal Structure Prediction: Exploring the Mendeleev Table as a Palette to Design New Materials →

EPFL (Lausanne, Switzerland),  May 21-24, 2019

Today, many open questions in computational science call for more than individual computations using a single code. As the demand for integration and throughput increases, the skill of writing robust and reproducible workflows is becoming ever more important. In this context, the move towards open science raises the level of scrutiny and demands that workflows be recorded in a way that can be inspected and reused by scientific peers.

This hands-on tutorial introduced young researchers to writing reproducible computational workflows using the open-source AiiDA framework for workflow management and provenance tracking (http://​www.aiida.net​), complemented by invited talks from experts in the field that highlight the power and the challenges involved with leveraging complex workflows in computational materials science.

Continue reading Writing reproducible workflows for computational materials science →

General comments

The Atomistic Simulation of Carbon and related Materials (ASCM2019) workshop (ascm2019.nanocarbon.fi) took place in Helsinki, Finland between the 10th and 12th of April 2019. The workshop venue was the historical main building of the University of Helsinki. The event was jointly organized by Flyura Djurabekova (University of Helsinki), Volker Deringer (University of Cambridge) and Miguel Caro (Aalto University).

A total of circa 45 participants (mostly from Europe but also from overseas) met at the heart of Helsinki for three days of discussion on the state of the art and future prospects of atomistic simulation of pure carbon compounds and nanostructures, functionalized carbon materials, carbon-containing molecules and silicon/SiC alloys. Focus topics with strong presence at the workshop were atomistic modeling of graphene and carbon nanotubes, amorphous carbon, molecular dynamics simulations of high-energy/irradiation effects, development and benchmarking of interatomic potentials and, prominently, machine learning applied to atomistic simulations in general and carbon science in particular. The oral sessions featured a nice combination of established and early-career researchers.

Continue reading ASCM2019 →

Objectives:

The main objective of the workshop “Green’s function methods: the next generation”, arrived at its 4-th edition, is to bring together an interdisciplinary audience of researchers dealing with Green’s functions methods and electron correlation. Both fundamental developments and high-end applications are targeted, together with discussions on numerical implementations and their current limitations.

Green’s functions have always played a prominent role in many-body physics. In particular the one-body Green’s function (GF) delivers a wealth of information about a physical system, such as ground-state energy, excitation energies, densities and other measurable quantities. Therefore the development of approximate methods to calculate the one-body GF has been an active research topic in many-body physics since the 60’s, and many routes have been explored in order to find increasingly accurate GFs. A very popular class of methods is based on the iterative solution of an integral equation for the GF containing an effective potential, the so-called self-energy, which needs to be approximated. The well-known GW approximation belongs to this class; this approximation is the method of choice for calculating band structures, but it also shows several shortcomings, such as the wrong description of satellites in photo-emission spectra, in particular in so-called strongly-correlated materials. Therefore more refined levels of approximations are needed to keep the pace with the advances made in experiment. Recently much progress has been made in this direction both by going beyond standard methods and also exploring completely novel routes to calculate GF. A new wave of original ideas, understanding, and solutions, has pervaded the field and was represented in the present workshop.

Continue reading Report on Green’s function methods: the next generation →

Workshop Report
What about U in nanoscale systems?

ZCAM/BIFI, Zaragoza, Spain, May 21-24 2019

Organizers: David Jacob (UPV/EHU, San Sebastian), Massimo Capone (SISSA, Trieste), Silke Biermann (Ecole Polytechnique, Paris)

Local Organizers: Beatriz Antoli, Adrian Velazquez-Campoy (ZCAM, BIFI, Zaragoza)

The Workshop “What about U in nanoscale systems?” took place at the CECAM node in Zaragoza from May 21 to May 24 2019. It followed the format of previous What about U editions, bringing together colleagues from different communities (including experimentalists) and providing ample discussion time. The new aspect this year was the focus on nanoscale systems, while also general aspects of correlations found their place. Continue reading What about U in nanoscale systems? →

The workshop aimed at bringing together experimentalists and theorists dealing with electronic structure investigations in correlated materials. Strongly correlated materials are notoriously difficult to describe theoretically due to the competing energy scales and emerging phenomena (like the Kondo effect) coming into play while at the same time experiments can provide a wealth of results whose interpretation often proves overwhelmingly challenging. It is therefore pivotal to bring together physicists investigating such materials theoretically or experimentally, to provide a common platform for discussions and encourage mutual insight into problems and results. This workshop aimed at exactly such an information exchange. Experimentally, recent advances in angle- and spin-resolved photoemission spectroscopy and scanning tunneling spectroscopy are leading examples for providing information about the materials’ electronic structure while cutting-edge density functional theory and dynamical mean field theory have developed into powerful tools for electronic structure calculations. Strongly correlated materials of interest ranged from transition metal compounds to f-electron systems. Of particular interest were also topological materials. Continue reading Workshop on Advances in Electron Spectroscopy – Experiment and Theory, April 14-17, 2019, Dresden →

The workshop took place in April 2019 in Göttingen and brought together leading researchers who develop and apply machine learning methods with the common goal of determining the fundamental properties of “small” molecules, biomolecules, and materials. These properties include high-dimensional potential energy surfaces, atomic densities, and molecular properties, such as dipole moments and polarizabilities. Communities in the areas of materials, biomolecules, gas-phase molecules and complexes have formed over the past ten or so years and a major objective of the workshop was to bring these communities together to hear and learn from each other’s experience.

Read the full report