Materials Science and Chemistry

(Image courtesy of the Tonner Lab)

Understanding and being able to manipulate material properties at the atomic level is important for the development of new technologies such as better batteries, smaller, more efficient computer chips, and more effective methods for generating and moving power. Supercomputing enables researchers to simulate the atomic-scale interactions in materials that determine their properties.

The following is a list of recent reports submitted by users of HLRS's high-performance computing systems describing their scientific interests and research results.

Click on each title for a more detailed report. The complete reports are found on the website of the Gauss Centre for Supercomputing (GCS), the alliance of Germany's three national supercomputing centers.

Validating CFD with Large-scale Molecular Dynamics Simulations
Computational fluid dynamics (CFD) simulations play an important role in today’s science and technology. Therefore, it is crucial to validate its underlying methods and models. This can be done by experiments or with molecular dynamics (MD) simulations, but in some cases only the latter are applicable. Since MD simulations follow the motion of each molecule individually, they are computationally very demanding, but they rest on an excellent physical basis. In this project, large systems of several hundred million atoms are considered to study the thermo- and hydrodynamic behavior of fluids during shock wave propagation, droplet coalescence and injection. The results are compared to that of macroscopic numerical methods.
Principal Investigator: Jadran Vrabec
Affiliation: Chair of Thermodynamics and Process Engineering, Technische Universität Berlin

Computational Chemistry for Advanced Functionalization of Inorganic Surfaces
By applying approaches based on computational chemistry, researchers at the University of Marburg are addressing the challenge of designing functional materials in a novel way. Using computing resources at the High-Performance Computing Center Stuttgart, the scientists under leadership of Dr. Ralf Tonner model phenomena that happen at the atomic and subatomic scale to understand how factors such as molecular structure, electronic properties, chemical bonding, and interactions among atoms affect a material's behaviour.
Principal Investigator: Ralf Tonner
Affiliation: Computational Materials Chemistry, Philipps-Universität Marburg

Defect-Induced Phenomena in Perovskites under Realistic External Conditions (DEFTD)
Project DEFTD is focused on large scale computer simulations of the atomic, electronic and magnetic properties of novel materials for energy applications, first of all, fuel cells transforming chemical energy into electricity, and batteries. Understanding of a role of dopants and defects is a key for prediction of improvement of device performance which is validated later on experimentally. Addressing realistic operational conditions is achieved via combination with ab initio thermodynamics. The state of the art first principles calculations of large and low symmetry are very time consuming and need use of supercomputer technologies as provided at HLRS in Stuttgart.
Principal Investigator: Eugene A. Kotomin
Affiliation: Department of Physical Chemistry of Solids, Max-Planck Institute for Solid State Research, Stuttgart (Germany)

Granulation and Faraday Waves in Driven Quantum Systems
Granular matter is typically the result of random pattern formation in a solid, like breaking a glass or pulverizing a rock into pieces of variable sizes. Faraday waves are patterns that appear on a fluid that is perturbed by an external drive that oscillates in resonance. Faraday waves aren't random; in contrast to granular matter, these waves are regular, standing, periodic patterns, seen for instance in liquids in a vessel that is shaken. Surprisingly, granulation and Faraday waves can exist in quantum systems too and, even more surprisingly, they can be produced in the same quantum system: in a gas of trapped atoms cooled very close to absolute zero temperature. When the strength of interactions between atoms is modulated, a Faraday pattern is produced if the modulation is fast and weak, and a granular state is formed if the modulation is slow and strong.
Principal Investigator: Axel U. J. Lode(1) and Alexej I. Streltsov(2)
Affiliation: (1)Technische Universität Wien, now: Institute of Physics, Albert-Ludwig University of Freiburg, (2) Institute of Physical Chemistry, Universität Heidelberg

Molecular Dynamics Simulations of Al-Mg-Alloys
The DFG Project SCHM746/154-1 has the objective to investigate strengthening mechanisms in aluminum magnesium alloys using molecular dynamic simulations. Simulating tensile tests in the very short accessible time is leading to high strain rates. These high strain rates together with the limited size of the simulated model is repeatedly leading to retention towards findings by molecular dynamic simulations. To overcome these stigmata, a short insight into two investigations are presented in this project overview, where a good connection between experimentally obtained and simulated results is made.
Principal Investigator: Martin Hummel
Affiliation: Universität Stuttgart, Institut für Materialprüfung, Werkstoffkunde und Festigkeitslehre (IMWF)

Frequency-Dependent Dielectric Polarizability of Nanocolloids and Polyelectrolytes in Electric Fields
Being able to handle and manipulate large molecules or other nano-objects in a controlled manner is a central ingredient in many bio- and nanotechnological applications. One increasingly popular approach, e.g., in microfluidic setups, is to use dielectrophoresis. Here, the nano-objects are exposed to an alternating electric field, which polarizes them. Depending on the polarization, they can then be grabbed and moved around or trapped by an additional field. However, the mechanisms governing the polarization of the objects, which are typically immersed in a salt solution, are very complicated. Simulations allow to disentangle the different processes that contribute to the polarizability and to assess the influence of key factors such as AC frequency, salt concentration, or salt diffusivity.
Principal Investigator: Jiajia Zhou, Friederike Schmid
Affiliation: Institute of Physics, Johannes Gutenberg University Mainz (Germany)

Two-Dimensional Inorganic Materials Under Electron Beam: Insights from Advanced First-Principles Calculations
First-principles atomistic computer simulations which make it possible to simulate various materials without any input parameters from the experiment (except for the chemical elements the material consists of) are powerful tools in the modern materials science. Although they require supercomputers, they not only reproduce the structure and properties of the known materials, but also make it possible to predict new ones and describe the behavior of the system under various conditions, e.g., electron irradiation. In this project, irradiation effects in two-dimensional (2D) inorganic materials were studied with the main focus on transition metal dichalcogenides. The intercalation of Li atoms into bilayer graphene was also addressed.
Principal Investigator: Arkady V. Krasheninnikov
Affiliation: Helmholtz-Zentrum Dresden-Rossendorf (Germany)

Emergent Locality in Quantum Systems with Long Range Interactions
How fast can information travel in a quantum system? While special relativity yields the speed of light as a strict upper limit, many quantum systems at low energies are in fact described by nonrelativistic quantum theory, which does not contain any fundamental speed limit. Interestingly enough, there is an emergent speed limit in quantum systems with short ranged interactions which is far slower than the speed of light. Fundamental interactions between particles are, however, often of long range, such as dipolar interactions or Coulomb interactions. A very-large scale computational study performed on Hazel Hen revealed that there is no instantaneous information propagation even in the presence of extremely long ranged interactions and that most signals are contained in a spatio-temporal light cone for dipolar interactions.
Principal Investigator: Fabien Alet (1) and David J. Luitz (2)
Affiliation: (1) Centre national de la recherche scientifique (CNRS), Toulouse University, France, (2) Max Planck Institute for the Physics of Complex Systems (MPIPKS), Dresden, Germany

Sulfur in Ethylene Epoxidation on Silver
One of the most influential chemicals in our daily lives is something many of us will never see: ethylene oxide. This chemical is a critical ingredient in our modern world, used to make everything from the plastic fibers of our clothes to the lubricants in our cars. Virtually all of it is produced by the catalytic reaction of ethylene and oxygen over a silver surface but, while this process has been known since 1931, just how it happens has remained a mystery. Researchers have used high-performance computing to gain new insight into this mystery by identifying the structure of the active catalyst surface and showing how it mediates the reaction of ethylene and oxygen to form ethylene oxide.
Principal Investigator: Travis Jones
Affiliation: Fritz-Haber-Institut der Max-Planck-Gesellschaft, Department of Inorganic Chemistry, Berlin (Germany)