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LINUX Cluster Project

Physikalische Eigenschaften niederdimensionaler Halbleiter


Institution

  • Name: Zentralinstitut für Physikalische Grundlagen d. Halbleiterelektronik - Walter Schottky Institut (WSI)
  • Address: Am Coulombwall 4, 85748 Garching
  • Project Proposal Date: 2018-03-19 16:25:55

Abstract:

1.Im wesentlichen gehts um das Kompilieren eines Executables für Linux-Plattformen, da an unserem Lehrstuhl kein Linux-System vorhanden ist. Zum Rechnen werde ich das Cluster höchstwahrscheinlich nicht benutzen, da wir ein eigenes Windows-64bit-Cluster haben. Evtl. sind ein paar Benchmarks geplant. 2.Aromatic adsorbates shall be investigated with quantum chemical techniques including dispersion interactions (second order Moller-Plesset perturbation theory, MP2). Electronic and vibrational excitations of molecules and clusters of molecules shall be calculated with density functional theory (DFT) and time-dependent DFT. The understanding of several properties of molecular materials requires investigations of intermolecular interactions, so that groups of up to four molecules shall be investigated simultaneously. In order to avoid time-consuming geometry optimizations, several methods shall be benchmarked for molecular crystals where the geometry is known. 3.We have developed a self-consistent algorithm for determining non-equilibrium Green?s functions for charge transport and optical gain in mesoscopic semiconductor devices. We apply our method on the I-V characteristics, optical gain, as well as the temperature dependence of the current density for concrete devices such as terahertz quantum cascade structures, resonant tunneling diodes and n-i-n resistors. Phonon scattering, impurity, Hartree electron-electron and interface roughness scattering within the self-consistent Born approximation are taken into account. We have developed two different numerically efficient contact models and compare single-period results with a quasi-periodic NEGF calculation. The implementation of our algorithm requires for detailed numerical tests which is the major purpose of our project on the LRZ-cluster. 4.Der Halbleiter-Bauteil-Simulator "Nextnano" soll auch für Linux-Nutzer verfügbar gemacht werden. Dazu muß er auf Linux kompiliert und getestet werden. We intend to investigate carbon nanotubes and fullerenes with density functional methods, with special emphasis on the pressure dependence of their mechanical, thermodynamic and electronic properties. The doping of fullerenes and carbon nanotubes with boron or nitrogen shall be studied as a function of the number of dopants per fullerene or nanotube. As a result of these computational studies, we expect new insight into the influence of doping onto the electronic properties of the molecules, a topic of direct relevance for device applications of these organic materials. 5. The Quantum Sensing group led by Dr. Friedemann Reinhard at Walter Schottky Institute focuses on quantum sensors and their applications, particularly in the life sciences. In collaboration with the Graduate School of BioEngineering (GSB) and Prof. Dr. Bernhard Wolfrum we are trying to find visual cues for neural activity in microscopic images of biological cells. To achieve this, we will analyze video sequences with Convolutional Neural Networks (CNN). In a first step, an Autoencoder will be used to identify and enhance characteristic features in the cells' time dependent behavior. In the long run, we want to use additional voltage measurements as labels to perform supervised learning on the images. Due to the large amount of image data needed for training, we would like to use GPUs for that purpose.