Highlights

Scientists have been looking for real-world examples of Weyl semi-metals, that are topological materials with unique transport, optical and thermoelectric behavior. Many computational and experimental papers had described a compound of europium, cadmium and arsenic, EuCd2As2, as a Weyl semi-metal. But a new study just published by an international research team led by MARVEL’s Ana Akrap has found that it is instead a magnetic semiconductor.

A 10-year effort has led to a theoretical framework and a software package, called koopmans, that allows to obtain reliable spectral properties of molecules and materials with density functional theory. The framework is described in a new article by MARVEL researchers at EPFL, and last month a week-long school co-organised by MARVEL in Pavia saw students learning about Koopmans functionals and trying out the code.

A research group including MARVEL scientists has developed, studied computationally and tested a transistor based on strips of graphene with widths of only a few nanometers, thanks to a new fabrication technique that overcomes the current challenges in making electrical contacts between graphene nanoribbons and electrodes.  

EPFL researchers make theoretical breakthrough in thermoelectric material to better harness waste heat for sustainable energy.

The collection of 2D materials, first initiated  in 2018, has been expanded with 1,252 new monolayers that could be exfoliated from existing tridimensional structures.

A new study by Berend Smit’s group at EPFL introduces a new computational framework that allows to screen large numbers of Covalent Organic Frameworks (COFs) in a fast and efficient way, to pre-select the best candidates for specific photocatalytic applications, such as water splitting. Starting from a set of 419 COFs for which there are reported experiments, the workflow allowed the selection of 13 candidate materials for water splitting. 

Quantum computing holds great promises for computational material science. A new project added to NCCR MARVEL at the beginning of Phase III wants to explore the potential of the current generation of hybrid systems - that combine a classical machine with a quantum one – for the simulation of electronic structures. Project leader Giuseppe Carleo explains how the group will develop new algorithms and novel machine learning strategies to run on these machines and improve the accuracy of current modelling methods. “The classical part does the heavy lifting and brings you very close to the exact solution," he explains, "and then you hope the quantum part gives you the extra step to reach the final accuracy".

A new method developed by the NCCR MARVEL laboratory of Michele Ceriotti at EPFL allows modelling alloys containing up to 25 transition metals, matching a remarkable accuracy with a manageable requirement of data and computational resources. The group validated the model and used it for computational experiments on three representative alloy compositions. In the future the model will be expanded to predict the catalytic behaviour of the surfaces of high-entropy alloys.

A new method developed by the NCCR MARVEL laboratory of Michele Ceriotti at EPFL allows modelling alloys containing up to 25 transition metals, matching a remarkable accuracy with a manageable requirement of data and computational resources. The group validated the model and used it for computational experiments on three representative alloy compositions. In the future the model will be expanded to predict the catalytic behaviour of the surfaces of high-entropy alloys.

NCCR MARVEL researchers have applied DFT with extended Hubbard functionals (DFT+U+V) to the study of two candidate cathode materials belonging to the class of lithium-manganese-oxide spinels. They used a new approach to determine the Hubbard U and V parameters entirely from first principles and found that the method accurately predicts the geometrical properties, oxidation states, band gaps, and voltages of the two materials. The article was included in the "2023 PCCP HOT Articles" collection.

Researchers including NCCR MARVEL’s Professor Ana Akrap at the Department of Physics at the University of Fribourg used Landau-level spectroscopy to determine the temperature dependence of the energy band gap in zirconium pentatelluride (ZrTe5). They found that the band gap is non-zero at low temperatures and increases monotonically when the temperature is raised, adding to evidence that ZrTe5 is a weak topological insulator. 

An ETHZ team led by Prof. Sereina Riniker, Associate Professor of Computational Chemistry at the Department of Chemistry and Applied Biosciences, has developed an alternative strategy for parametrizing intermolecular interactions. Described in the paper “Regularized by Physics: Graph Neural Network Parametrized Potentials for the Description of Intermolecular Interactions,” recently published in the Journal of Chemical Theory and Computation, the approach accelerates and simplifies the parametrization process of classical force fields and can take advantage of large data sets. Used in combination with machine learning-based techniques, the model allows researchers to take advantage of the best of both, and access a universal optimization toolkit combined with robust and physically constrained models.