Our research group uses advanced computational methods to design sustainable materials for diverse applications, including semiconductor devices, spintronics, neuromorphic devices, thermoelectrics, and energy storage devices. We develop scalable machine learning frameworks to improve density functional theory simulations, connect microscopic and mesoscopic simulations, and model advanced material properties.
Dr Attila Cangi
CASUS Research Team Leader
Contact
+49 3581 375 23 52
Center for Advanced Systems Understanding
Conrad-Schiedt-Straße 20
D-02826 Görlitz
Svetoslav Nikolov, Kushal Ramakrishna, Andrew Rohskopf, Mani Lokamani, Julien Tranchida, John Carpenter, Attila Cangi, Mitchell A. Wood - PNAS December 12, 2024
Dynamic compression of iron to Earth-core conditions is one of the few ways to gather important elastic and transport properties needed to uncover key mechanisms surrounding the geodynamo effect. Herein, a machine-learned ab initio derived molecular-spin dynamics (MSD) methodology with explicit treatment for longitudinal spin-fluctuations is utilized to probe the dynamic phase-diagram of iron. This framework uniquely enables an accurate resolution of the phase-transition kinetics and Earth-core elastic properties, as highlighted by compressional wave velocity and adiabatic bulk moduli measurements. In addition, a unique coupling of MSD with time-dependent density functional theory enables gauging electronic transport properties, critically important for resolving geodynamo dynamics.
Attila Cangi, Lenz Fiedler, Bartosz Brzoza, Karan Shah, Timothy J. Callow, Daniel Kotik, Steve Schmerler, Matthew C. Barry, James M. Goff, Andrew Rohskopf, Dayton J. Vogel, Normand Modine, Aidan P. Thompson, Sivasankaran Rajamanickam - arXiv:2411.19617
We present the Materials Learning Algorithms (MALA) package, a scalable machine learning framework designed to accelerate density functional theory (DFT) calculations suitable for large-scale atomistic simulations. Using local descriptors of the atomic environment, MALA models efficiently predict key electronic observables, including local density of states, electronic density, density of states, and total energy. The package integrates data sampling, model training and scalable inference into a unified library, while ensuring compatibility with standard DFT and molecular dynamics codes. We demonstrate MALA’s capabilities with examples including boron clusters, aluminum across its solid-liquid phase boundary, and predicting the electronic structure of a stacking fault in a large beryllium slab. Scaling analyses reveal MALA’s computational efficiency and identify bottlenecks for future optimization. With its ability to model electronic structures at scales far beyond standard DFT, MALA is well suited for modeling complex material systems, making it a versatile tool for advanced materials research.
Attila Cangi - Nature Computational Science volume 4, pages 729–730 (2024)
A highly efficient reconstruction method has been developed for the direct computation of Hamiltonian matrices in the atomic orbital basis from density functional theory calculations originally performed in the plane wave basis. This enables machine learning calculations of electronic structures on a large scale, which are otherwise not feasible with standard methods, and thus fills a methodological gap in terms of accessible length scales…
Kushal Ramakrishna, Mani Lokamani, Attila Cangi - arXiv preprint arXiv:2409.15160
Understanding the electrical conductivity of warm dense hydrogen is critical for both fundamental physics and applications in planetary science and inertial confinement fusion. We demonstrate how to calculate the electrical conductivity using the continuum form of Ohm’s law, with the current density obtained from real-time time-dependent density functional theory. This approach simulates the dynamic response of hydrogen under warm dense matter conditions, with temperatures around 30,000 K and mass densities ranging from 0.02 to 0.98 g/cc. We systematically address finite-size errors in real-time time-dependent density functional theory, demonstrating that our calculations are both numerically feasible and reliable. Our results show good agreement with other approaches, highlighting the effectiveness of this method for modeling electronic transport properties from ambient to extreme conditions…
Thomas Gawne, Hannah Bellenbaum, Luke B Fletcher, Karen Appel, Carsten Baehtz, Victorien Bouffetier, Erik Brambrink, Danielle Brown, Attila Cangi, Adrien Descamps, Sebastian Goede, Nicholas J Hartley, Marie-Luise Herbert, Philipp Hesselbach, Hauke Höppner, Oliver S Humphries, Zuzana Konôpková, Alejandro Laso Garcia, Björn Lindqvist, Julian Lütgert, Michael J MacDonald, Mikako Makita, Willow Martin, Mikhail Mishchenko, Zhandos A Moldabekov, Motoaki Nakatsutsumi, Jean-Paul Naedler, Paul Neumayer, Alexander Pelka, Chongbing Qu, Lisa Randolph, Johannes Rips, Toma Toncian, Jan Vorberger, Lennart Wollenweber, Ulf Zastrau, Dominik Kraus, Thomas R Preston, Tobias Dornheim - Journal of Applied Physics, Volume 136, Issue 10, 14 September 2024
Mosaic crystals, with their high integrated reflectivities, are widely employed in spectrometers used to diagnose high energy density systems. X-ray Thomson scattering (XRTS) has emerged as a powerful diagnostic tool of these systems, providing in principle direct access to important properties such as the temperature via detailed balance. However, the measured XRTS spectrum is broadened by the spectrometer instrument function (IF), and without careful consideration of the IF one risks misdiagnosing system conditions. Here, we consider in detail the IF of 40 and 100 μ m mosaic Highly Annealed Pyrolytic Graphite crystals, and how the broadening varies across the spectrometer in an energy range of 6.7–8.6 keV. Notably, we find a strong asymmetry in the shape of the IF toward higher energies. As an example, we consider the effect of the asymmetry in the IF on the temperature inferred via XRTS for simulated …
CASUS
Untermarkt 20, D-02826 Görlitz
Conrad-Schiedt-Str. 20, D-02826 Görlitz
About
Events & Seminars
Scultetus
Publications
Career
Imprint
Privacy Policy
CASUS is an institute of Helmholtz-Zentrum Dresden-Rossendorf (HZDR)
Funded by:
in close cooperation with:
Funded by:
In close cooperation with: