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Research Interests

Stefan Blügel

Nano-Science-Lab: Supercomputer

We perform atomic-scale computer simulations to understand complex properties and processes in solids, at solid surfaces, of interfacial structures and nano-structures of a type relevant to basic science. The methodology employed is that of large-scale ab-initio quantum mechanical computer calculations at the scale of the individual atoms. It is the aim to understand the materials properties and processes on the level of the electronic structure. The quantum mechanical description of the electrons involved is based on the density functional formulation of quantum mechanics. Our interest is focussed towards REAL materials as in opposite to model systems. Forces caused by the electrons excerted on the atoms are used to describe the classical degrees of freedom of the atoms by molecular dynamics. This activity can be catagorized as solid state and material oriented computational physics at the supercomputing end.

The predictive power of the density functional theory is used and calculations are carried out

  1. to predict new materials, new processes and new effects (with little or no exp. input),
  2. to assist the analysis of experimental results or
  3. to produce information complementary to experimental results

Research interests

Our research interests centers around low dimensional systems and nano-structures such as

  1. magnetic multilayer, magnetic surfaces, ultrathin magnetic films, nano-magnets
  2. semiconductor (element IV, III-V, II-VI), surfaces, heterostructures, and dots
  3. semiconductor/magnetic-metal and oxid/metal junctions
  4. transport properties

and we investigate properties such as:

  1. electronic structure related quantities a. bandstructure, valence-band off-set, scanning tunneling spectroscopy and topography b. magnetic properties (magnetic moment, magn. structure, magn. anisotropy, hyperfine field)
  2. atomic structure and stability, surface alloys formation
  3. microscopic growth mechanism, modification of growth due to surfacants, role of stress

Ab initio methods

There is a constant on-going effort to develop new and improve existing computational methods. The different systems and different questions require different ab initio methods.

At present two methods are in use and under development, respectively:

  1. The full-potential linearized augmented plane-wave method (FLAPW-method).
  2. The plane-wave pseudopotential method implemented as (EStCoMPP program).

Collaborations

With this research aim in mind and methods at hand we developed a large record of collaborations with experimental groups:

IFF-IEE CarboneSpektroscopy at ultrathin magnetic films
IGVWuttigStructure and Growth of magnetic films
IFF-IEESauerHyperfinefields at internal interfaces
Uni HH Wiesendanger STM-Interpretation of laterally structured magnetic surfaces
IGV VoigtländerSurfactant mediated growth of semiconductor films
IFFEbert STM-Interpretation at semiconductor surfaces
IFF-IEE Eisebitt Soft X-ray emission spectroskopy (SXES)
ISILüthsemiconductor heterostructures
Uni-Würzbg. Steinrück BeSe, BeTe surfaces and heterostructures
ISI MantlSilicides

Those interested in Diplomarbeiten or Phd-thesis please contact me.

  • ab initio
  • The term ab initio means that the method is parameter free requiring only the atomic numbers and a initial guess of the electron charge density and of the atomic structure of the atomic species making up the material.

 


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