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Diamond Materials

Diamond Materials for Quantum Application

23. September 2014: The DFG research group FOR 1493 “Diamond Materials and Quantum Applications” goes into its second funding period. FOR1493 is a national research consortium funded by the Deutsche Forsch-ungsgemeinschaft.

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ERC Advanced Grant

ERC

Molecular dynamics simulation

Molecular Dynamics simulations have become a powerful tool for theoretically investigating a large number of systems. The major advantage of this numerical method is obvious, since it allows capturing the system dynamics with atomic spatial resolution, therefore delivering a microscopic picture of the process under investigation. The choice of describing the interactions between the atoms ranges from quantum mechanics to classical mechanics and has to be chosen according to the complexity of the system as well as the computation power at hand. Using empirical force fields and PC clusters, system sizes of up to 10 6 ~ 10 7 atoms are nowadays addressable in a time window of ns to µs.
One field of application of MD-simulations is the microscopic description of the dynamics and function of biomolecules and thus, the construction of a detailed picture of the relevant processes taking place inside the cell. A number of biological systems have been under investigation at the 3rd physics institute. The tumor necrosis factor receptor 1 (TNFR1) is a membrane receptor and plays a major role in programmed cell death (apoptosis) [Branschädel et. al (2010)]. The light harvesting complex LH1 is a pigment protein complex and a integral part of the bacterial photosynthesis machinery [Aird et. al (2007)]. SecYEG is a protein translocation channel and responsible for transporting proteins across as well as integrating proteins into the membrane.

A different research area deals with the simulation of covalent materials, particularly carbon. For example, bulk- as well as nanodiamonds containing impurities are promising candidates for a broad range of applications (quantum computing, magnetometry, biomarkers). A positioning accuracy on the nanometer scale and very small, nanometer sized diamonds containing stable defects are prerequisites for these applications. Using MD simulations together with potentials to describe covalent materials, like the Tersoff potential, carbon clusters with and without defects are investigated. Here, cluster sizes in the range of 10-100 nm can be described in the ns-µs time regime using High Performance Computing and parallel simulation codes.

This project investigates the structure and stability of carbon clusters subject to external mechanical as well as kinetic stress using molecular dynamics simulations. In addition, the stability of defects as a function of cluster size, distance to surface and external parameters is explored. Steps in the production process of carbon nanoclusters like milling, laser ablation or the systematic implantation of defects are numerically simulated on multiple scales with the objective to optimize target structures.