“Bite” defects revealed in bottom-up graphene nanoribbons

Two recently published papers from a collaboration between two NCCR MARVEL labs have identified a new type of defect as the most common source of disorder in on-surface synthesized graphene nanoribbons (GNRs), a novel class of carbon-based materials that may prove extremely useful in next-generation electronic devices. Combining scanning probe microscopy with first-principles calculations allowed the researchers to identify the atomic structure of these so-called "bite" defects and to investigate their effect on quantum electronic transport in two different types of graphene nanoribbon. They also established guidelines for minimizing the detrimental impact of these defects on electronic transport and proposed defective zigzag-edged nanoribbons as suitable platforms for certain applications in spintronics.

Superconductivity, high critical temperature found in 2D semimetal W2N3

Two-dimensional superconductors have drawn considerable attention both for the fundamental physics they display as well as for potential applications in fields such as quantum computing. Although considerable efforts have been made to identify them, materials with high transition temperatures have been hard to find. Materials that feature both superconductivity and non-trivial band topology, a combination that could potentially give rise to exotic states of matter, have proven even more elusive. In the paper Prediction of phonon-mediated superconductivity with high critical temperature in the two-dimensional topological semimetal W2N3 , recently published in Nano Letters, researchers predict just such a material in the easily exfoliable, topologically non-trivial 2D semimetal W2N3.

Low-temperature crystallization of phase-pure α-formamidinium lead iodide enabled by study in Science Advances

Perovskite solar cells (PSCs) are among the most promising and cheapest photovoltaic technologies now available, but widespread application has been hampered by issues linked to long-term stability and processability. In the paper A combined molecular dynamics and experimental study of two-step process enabling low-temperature formation of phase-pure α-FAPbI3, recently published in Science Advances, researchers including Prof. Michele Parrinello, professor of computational Sciences at the Università della Svizzera italiana and ETHZ as well as Group Leader in NCCR MARVEL's Design & Discovery Project 1, and Paramvir Ahlawat,  a PhD student in the EPFL Lab of Prof. Ursula Roethlisberger, address this problem with a combined experimental and simulation study that could improve the design of industrial-scale processing techniques for MAPbI3 and FAPbI3, two lead perovskites.

Landau levels serve as probe for band topology in graphene Moiré superlattices

Researchers led by Oleg Yazyev, head of the Chair of Computational Condensed Matter Physics at EPFL, have determined a straightforward method for probing the topological character of electronic bands in two-dimensional Moiré superlattices using Landau level sequences. The results can be easily extended to other twisted graphene multilayers and h-BN/graphene heterostructures, making the approach a powerful tool for detecting non-trivial valley band topology. The paper Landau Levels as a Probe for Band Topology in Graphene Moiré Superlattices was recently published in Physical Review Letters.

“Ghost particle” ML model permits full quantum description of the solvated electron

Pinning down the nature of bulk hydrated electrons—extra electrons solvated in liquid water—has proven difficult experimentally because of their short lifetime and high reactivity. Theoretical exploration has been limited by the high level of electronic structure theory needed to achieve predictive accuracy. Now, joint work from teams at the University of Zurich and EPFL and colleagues has resulted in a highly accurate machine-learning (ML) model that is inexpensive enough to allow for a full quantum statistical and dynamical description, giving an accurate determination of the structure, diffusion mechanisms, and vibrational spectroscopy of the solvated electron. This new approach, outlined in the Nature Communications paper Simulating the Ghost: Quantum Dynamics of the Solvated Electron, could also be applied to excited states and quasiparticles such as polarons and would allow for high-accuracy simulations at a moderate price.

MARVEL and CSCS: a partnership built for exa-scale computing in materials science

The NCCR MARVEL has ‘Materials’ revolution’ in its name for a reason: it seeks to radically transform and accelerate the process of materials discovery and design. It seeks to do this by taking a computational approach, built on a platform of database-driven, high-throughput quantum simulations: if we could compute the properties of every material using electronic structure calculations, and if we could use that information to screen big databases for materials with just the right characteristics for a given purpose — then that would put us at an enormous advantage in the search for new and better materials, avoiding much of the trial and error that comes with experiments in the lab. Such a project requires robust computer resources. For one, the sort of calculations that MARVEL research relies on take a lot of computing time and data storage; as those calculations get ever more sophisticated, demands on computing power will only grow. For another, to turn the MARVEL project into a true revolution, computer resources must be organised in such a way that they can serve as a platform for the broader materials science community.

MARVEL Review and Retreat January 2025

The eleventh MARVEL Review and Retreat will take place on January 13-15, 2025. The event will gather all MARVEL members, group leaders as well as postdocs and students. Presentations will show to all the community where the projects stand and what are the next steps. 

CECAM-MARVEL Classics in molecular and materials modelling: David Ceperley and Claudia Filippi

David Ceperley (University of Illinois Urbana-Champaign, USA) and Claudia Filippi (University of Twente, NL) will give a joint lecture on "Quantum Monte Carlo, in what will be the 11th event in the series "Classics in molecular and materials modelling" hosted by CECAM and MARVEL.

MARVEL Distinguished Lecture — Gerbrand Ceder

The 39th NCCR MARVEL Distinguished Lecture will be given by Prof. Gerbrand Ceder (University of California, Berkeley). 

CECAM-MARVEL Mary Ann Mansigh series: Science and diplomacy

CECAM and MARVEL present a new event in our Mary Ann Mansigh Conversation series. In these complex times, we believe that the theme of Science and Diplomacy is of utmost relevance. We plan to address it from points of view that include education and scientific exchange in developing countries, the potential of computational science as a facilitator for diplomacy, actions of international institutions promoting peace and disarmament, and the management of cooperative research infrastructures in problematic areas.

MARVEL Distinguished Lecture — Alexandre Tkatchenko

The 39th NCCR MARVEL Distinguished Lecture will be given by Prof. Alexandre Tkatchenko, University of Luxembourg. He will be presenting a lecture entitled: "AI-Driven Fully Quantum Biomolecular Simulations".

MARVEL Distinguished Lecture — Darío Gil

The 25th NCCR MARVEL Distinguished Lecture will be given by Dr. Darío Gil, Senior Vice President and Director of IBM Research on "The Era of Accelerated Materials Discovery".

Materials Cloud as official repository for Open Research Europe

We are very pleased to announce that the Materials Cloud platform developed by the NCCR MARVEL is now an official repository for Open Research Europe.

AiiDA team wins PRACE-funded resources to deploy AiiDAlab web platform

The AiiDA team has been granted computing resources from the Fenix Research Infrastructure in the third PRACE-ICEI call for proposals. Having gained 84 CPUs, 1 TB RAM memory, 2.5 TB storage, and 40 TB in archive space from the CSCS Swiss National Supercomputing Centre in the call, the team will be able to strengthen high-performance and high-throughput computing research through a more powerful deployment of the AiiDAlab web platform.