First-principles electronic structure calculations are based on the laws of quantum mechanics and only use the fundamental constants of physics as input to provide detailed insight into the origin of mechanical, electronic, optical and magnetic properties of materials and molecules.
Both structural and spectroscopic information is directly obtainable from high-performance computations and yields information which is complementary to that obtained from TEM.
Accurate results on energetics (e.g. thermodynamic stability), atomic positions and lattice parameters are obtained from calculations within the density functional theory (DFT) formalism, which often provides also a good starting point for the calculation of electronic and optical properties with more advanced many-body calculations (GW, Bethe-Salpeter equation).
Electron energy core-loss spectra are calculated both within the DFT and the real-space-multiple-scattering formalism.
Current research activities are focused on :
- atomic positions at grain boundaries e.g. in CIGS photovoltaic cells
- thermodynamic stability of layered thermoelectrics in the Bi-Sb-Te-Se system
- core-loss and low electron energy loss spectra (EELS, ELNES)
- structural and electronic properties of point defects in semiconductors and insulators
- calculation of electronic structure factors and Debye-Waller factors