The Psi-k Community

MISSION: Psi-k is a Europe-based, worldwide network of researchers working on the advancement of first-principles computational materials science. Its mission is to develop fundamental theory, algorithms, and computer codes in order to understand, predict, and design materials properties and functions. Theoretical condensed matter physics, quantum chemistry, thermodynamics, and statistical mechanics form its scientific core. Applications encompass inorganic, organic and bio-materials, and cover a whole range of diverse scientific, engineering, and industrial endeavours. Key activities of Psi-k are the organization of conferences, workshops, tutorials and training schools as well as the dissemination of scientific thinking in society.

Psi-k is a bottom-up researchers’ network, established in 1994, to build strength and cooperation in the field of computational electronic structure. Psi-k activities are coordinated by a Board of Trustees, a Scientific Advisory Committee, and 16 Working Groups. These activities encompass the organization or co-sponsoring of ~30 workshops, conferences, schools or tutorials every year, an annual research conference jointly with CECAM, and a major conference covering the entire field every 5 years.

In addition, Psi-k produces a regular newsletter with extensive scientific highlights, and allows researchers to advertise job openings, events, and other topics of mutual interest through its 5000+ members mailing list.

This new website — introduced in  2015 to replace a venerable old site that provided sterling service over many years — offers a much more flexible modern design and functionality and it is to be hoped that it will provide even more stimulus for collaboration and cooperation amongst its members. Instructions regarding how to use it are here.

Ab Initio Spin Modelling Workshop

CECAM-HQ-EPFL, Lausanne, Switzerland, 26-28 November 2018

Organizers: Jerome Jackson and Martin Lüders, STFC Daresbury Laboratory, UK

http://www.cecam.org/workshop-0-1549.html

32 speakers and participants took part in the Psi-k, CCP-magnetism and CECAM financed Workshop on the subject of Ab Initio Spin Modelling, which was held at CECAM-HQ, Lausanne, between 26—28 November 2018. The format of the event was designed to foster discussion between groups working on diverse problems in the ab initio treatment of magnetism in solids. Talks of approximately one hour by the invited speakers were interspaced with much lively and enjoyable discussion. The long talks were intended to allow detailed, in depth presentations and this was indeed the outcome. The speakers represented work in quite different methods with electronic structure (e.g., from fully relativistic KKR to perturbation theory based on pseudopotentials/plane waves) – this seemed, if anything, to motivate and promote questions and active involvement by all the participants. Productive discussion also took place during the poster sessions where the quality of the poster presentations was extremely high.

Read the full report here.

CAMD Summer School 2018

The Psi-k sponsored “CAMD Summer School 2018 Electronic Structure Theory and Materials Design” took place in the week August 12-17, 2018 at Strandhotel Marienlyst in Helsingør, Denmark. Thanks to the more than 100 external attentive summer school students and the 15 very helpful invited lecturers, the school was the nice success that we had hoped for. The school taught PhD students from all over the world the basic and more advanced concepts in modern electronic structure theory including ground state density functional theory (DFT), many-body methods materials informatics and machine learning. Emphasis was put on the methodology applied “on-top” of ab-initio calculations which is essential for the computational design of new functional materials.

Read the full report here.

Final report on psi-k funded Elk workshop

Organizers: J. K. Dewhurst, E. K. U. Gross, and S. Sharma

1.  SUMMARY

The Psi-k funded Elk-code  tutorial  took place at the Max Planck Institute of Microstructure Physics (MPI-Halle) in Halle, Germany,  from September 3 – 7, 2018. There were a total  of 14 speakers and tutors of the code and 45 students from 16 countries. We were oversubscribed and ,unfortunately, had to turn down several applicants (we received in total 61 requests for attending the Elk-tutorials).

The Elk LAPW  code (http://elk.sourceforge.net/) is an electronic structure code based on the state-of-the-art full-potential  linearized augmented plane-wave (LAPW)  method. It was designed from the start to be a user- and developer-friendly code, allowing PhD students and post-docs to both use the code for their  research as well as implement new ideas in the field of electronic structure.

The present Elk-tutorial  was fourth in the series of tutorials.  The previous tutorials were held in 2011, 2013 and 2015. The aims of the tutorials  have been introduction  to the ELK  code as well as the cutting  edge science and implementations in the field of electronic structure methods.

Continue reading Final report on psi-k funded Elk workshop

Report on the Psi-k/CECAM Research Conference “Ab initio Spin-Orbitronics”

September 25, 2017 – September 29, 2017
Hotel Promenade, Montesilvano, Pescara (Italy)

Organizers:
Silvia Picozzi (Consiglio Nazionale delle Ricerche CNR-SPIN, Italy)
Stefan Blügel (Forschungszentrum Jülich, Germany)
Ingrid Mertig (Martin Luther University Halle, Germany)

The main purpose of this Psi-k/CECAM research conference (with about 110 participants) has been to highlight the very recent theoretical and computational developments related to the interplay of spin-orbit interaction with electronic structure, magnetism, transport as well as its link to strongly correlated materials and ultrafast currents in diverse materials. We have focused on discussing spin-orbit coupling (SOC) as a means of engendering fundamentally novel physical phenomena in exotic systems. The Conference therefore spanned several research dimensions, ranging from Materials (in the form of bulk compounds, surfaces and interfaces, thin films and heterostructures) to Functionalities (associated with topology, spin-momentum locking, valley degrees of freedom, skyrmions, coupling to electric currents by Berry phases, etc.) to method developments (in terms of dynamical processes in out-of-equilibrium quantum matter, Berry phase physics, etc). A brainstorm about concepts and ideas in a little understood phenomenon, such as orbital magnetization, was carried out under the guidance of Prof. Ivo Souza. While the main focus was on ab initio simulations, a few leading scientists in experiments were invited (Prof. Stuart Parkin, Prof. Claudia Felser, etc) and a strong interface to many-body physics treated on the basis of realistic model Hamiltonians was included.

Read the full report here.

Report on CECAM Workshop: “Emerging Technologies in Scientific Data Visualisation”.

Title: Emerging Technologies in Scientific Data Visualisation
Location: CECAM-IT-SISSA-SNS Node, in Scuola Normale Superiore (Pisa, Italy)
Webpage with list of participants, schedule and abstracts of presentations: https://www.cecam.org/workshop-1586.html

Dates: April 4, 2018 to April 6, 2018
Organizers:

Stefano de Gironcoli (International School for Advanced Studies (SISSA) and CNR-DEMOCRITOS IOM, Trieste, Italy)

Emine Kucukbenli (SISSA, Trieste, Italy)

Giordano Mancini (Scuola Normale Superiore, Pisa, Italy)

Monica Sanna (Scuola Normale Superiore, Pisa, Italy)

State of the art:

Visualisation allows us to tap into high-bandwidth cognitive hierarchies of our brains and allows us to process high densities of information at once. In the field of atomistic and molecular simulations, it is a key element to research: we use ball-and-stick figures to represent the simulation scenarios, graphs to recognize or communicate parametric relationships of equations. The “Big Data” trend gave rise to several projects with vast output of data, many data-driven approaches are being introduced. For instance, a new EU Center of Excellence, “NOMAD”, is established to collect, store and regularize data to build a materials encyclopedia. Continue reading Report on CECAM Workshop: “Emerging Technologies in Scientific Data Visualisation”.

Report: Workshop on Electronic Structure Theory with Numeric Atom-Centered Basis Functions 2018, July 9-11, Munich

Participants of the workshop attending one of the seminars.

This workshop held July 9 to 11, 2018, focused on methods that leverage localized, numeric atom-centered orbital (NAO) basis functions, a choice upon which a number of the strongest available electronic structure developments are founded. The workshop brought together key players from the FHI-aims code and related European and international efforts to highlight, discuss, and advance the state of the art of NAO-based modeling of molecules and materials based on the first principles of quantum mechanics. This workshop covered three days and 23 invited talks, covering:

  • development of community-based, shared infrastructure projects for electronic structure theory (Garcia, Larsen, Pouillon),
  • benchmarking efforts to assess and improve the accuracy of approximations used in electronic structure theory (Al-Hamdani, Goedecker, Liu),
  • applications of density functional perturbation theory (Laasner, Raimbault, Shang),
  • automation of workflow via machine learning and “big data” efforts (Ghiringhelli, Hoja),
  • scalability towards large systems and exascale computational resources (Huhn, Scheurer, Yu),
  • numerical algorithms and new methods for NAO-based electronic structure theory (Hermann, Ringe, Rossi), and
  • extensions beyond standard Kohn-Sham DFT (Golze, Havu, Michelitsch, Oberhofer, Ren)

Continue reading Report: Workshop on Electronic Structure Theory with Numeric Atom-Centered Basis Functions 2018, July 9-11, Munich

Report: CECAM/Psi-k Workshop Bremen on Reliable and quantitative prediction of defect properties in Ga-based semiconductors

CECAM Report

Program GASC

Organizers: Thomas Frauenheim (Bremen), Peter Déak (Bremen), Klaus Irmscher (Berlin), Susanne Siebentritt (Luxembourg),  Joel B. Varley (Livermore, California)

Venue: University of Bremen, Bremen Center for Computational Materials Science (BCCMS), Germany, 8th until 12th of October 2018

Sponsors: University of Bremen (BCCMS), Psi-k, DFG

Defect engineering in micro/optoelectronics and in photovoltaics has immensely profited from electronic structure calculations. In the past two decades, local and semi-local approximations of density functional theory were the workhorses of theoretical studies but, by now, it has become clear that they do not allow a sufficiently accurate and reliable prediction of defect properties in wide band gap materials. While ab initio energy methods for calculating the total energy are struggling with the system sizes necessary for defect modeling, semi-empirical methods using various corrections or hybrid functionals are being applied for the purpose. While the theoretical background of these methods and their relation to each other is by now more or less understood, the transferability of the semi-empirical parameters and the overall predictive power is still unclear. Progress requires further systematic testing and comparison of the various methods, as well as validation against experiments. For that, accurate measurement data on defects are needed on a set of materials, which are structurally or compositionally related. Gallium based semiconductors, like GaN, Ga2O3 and CuInxGa1-xSe(S)2 chalcogenides (CIGS) offer a good possibility for testing theory and are interesting also experimentally due to their versatile applications.

While there are still open defect-related questions in the much studied blue LED-material GaN, very few defects could be positively identified as yet in CIGS solar cell materials, while the research on the potential power semiconductor and UV transparent electrode Ga2O3 has barely started. Following the successful workshops on Gallium Oxide and Related Materials, held in Kyoto (Japan) in 2015, and in Parma (Italy) in 2017, as well as several workshops on chalcogenide photovoltaic materials, e.g., Symposium V at the E-MRS Spring meeting 2016, the CECAM-workshop in Bremen 2018 will focus on bringing together experimentalist interested in gallium oxide and Ga-based chalocgenides with theorists who are active in the field. A friendly and stimulating environment will facilitate discussions, adding impetus to both the development of practically applicable theoretical methods and to progress in the defect engineering of these materials.

Workshop Report:”Modern Approaches to Coupling Scales in Materials Simulation”

Our workshop was held from the 2nd to the 4th of July at the Hotel Jäger von Fall which sits on a peninsula on the Sylvensteinsee, an artificial lake in the Bavarian foothills of the Alps near the Austrian border. This is a very remote location chosen deliberately to allow participants to concentrate fully on the scientific program. Transportation from and to the nearest train station was accomplished with a shuttle-bus courtesy of the Technical University of Munich (TUM), driven by some of the participating TUM members. For the most part the weather was very inviting, inspiring a small number of participants to take a refreshing swim during the breaks, it turns out that the water was very clear but also very, very cold.

The two evenings of the workshop where filled with a poster-session on Monday, held outdoors due to the lovely weather, and a conference dinner, again outdoors, on Tuesday.

The event was supported by Psi-k, the German science foundation (DFG), the international graduate school of science and engineering (IGSSE), as well as the Technical University of Munich.

Workshop Report: “Theoretical methods in molecular spintronics” (TMSpin)

The Workshop “Theoretical methods in molecular spintronics (TMSpin) was held at the Materials Physics Center of the University of the Basque Country in Donostia-San Sebastian from the 17th to the 20th of September 2018. This workshop welcomed 31 invited speakers and several postgraduate students presenting posters. The event was co-sponsored by Psi-k and the Donostia International Physics Centre (DIPC- http://dipc.ehu.es/).

Molecular spintronics is the study of spin-related phenomena in molecules and atoms and their possible applications for the next generation of data storage and processing devices as well as for the implementation of quantum computers. Electronic structure theory has played a prominent role in molecular spintronics. The comparison of theory and experiments has demonstrated the importance of first-principles calculations, which go beyond model representations of molecular devices as simple “quantum dots” or effective spin Hamiltonians. Nonetheless, standard electronic structure methods based on Density Functional Theory often fail in describing molecular spintronic systems even at a qualitative level. This is because most magnetic phenomena are manifestations of correlation effects, which become extreme at the single molecule scale and which are not captured by standard implementations and approximations of DFT. The goal of TMSpin was to address the question:

“What electronic structure theory to use for molecular spintronics?”

The workshops gathered theoretical physicists and quantum chemists with different areas of expertise. On the one hand there were those researchers that have provided important contributions to the advancement of molecular spintronics since its inception. They were asked to give an overview about the field and moreover to highlight the open questions that to date cannot yet be addressed by theory. On the other hand, the workshop gathered some of the leading researchers in theory and code development, who presented the most recent fundamental and numerical advancements for a number of methods. The organizers promoted an intense discussion to understand whether such methods can be already employed in molecular spintronics. Continue reading Workshop Report: “Theoretical methods in molecular spintronics” (TMSpin)

Ab initio (from electronic structure) calculation of complex processes in materials