3rd Workshop on ab initio phonon calculations
Invited speakers:
- Peter Blaha, Electronic structure and atomic forces by WIEN2k
- Alexei Bosak, Less common combinations of inelastic scattering with first principles calculations
- Mark Johnson, Experimental and computational studies of vibrations in inter-molecular hydrogen bonds: from crystals to DNA
- Gordon J. Kearley, Determination of the symmetry of ferroelectric phase of SrTi18O3 from lattice dynamics calculations
- Krzysztof Parlinski, Material properties studied with Phonon
- Helmut Schober, Relationship between phonons and thermal expansion in Zn(CN)2 and Ni(CN)2 from inelastic neutron scattering and ab-initio calculations
- Elwira Wachowicz, t of impurities on structural, cohesive, and magnetic properties of grain boundaries in α-Fe
- Wilfried Wunderlich, Ab-initio phonon calculations, Photo-emission-, Raman- and Seebeck-data at (Fe,Co)Si
- Mohamed Zbiri, Phonon spectra In the oxygen-free FeAs pnictides: Insights from ab-Initio lattice dynamical calculations and inelastic neutron spectroscopy
Scope:
Phonons are present in any crystalline material. They determine the system temperature.
Moreover, they describe the spectroscopic properties, many macroscopic quantities, like elastic constants, mean square displacements, dielectric constant, heat capacity, heat conductivity, superceonductivity, ferroelectricity, diffusion, play a significant role in phase transitions, phase diagrams, chemical reactions, etc. Phonon properties are modified by the presence of defects, disorder, grain boundaries, dislocations, show specific behaviour on surfaces, decorated surfaces, interfaces and amorphous systems.
A deep understanding of phonons is especially important in systems featuring strong electron-phonon and/or magnetic-phonon couplings. Phonons are measured by a number of sophisticated techniques: inelastic coherent and incoherent neutron scattering, coherent x-ray scattering, nuclear inelastic scattering, infrared absorption, and Raman scattering.
The main goal of the Workshop is to review the method of calculating phonons in crystalline systems, which is based on supercell approach and uses the Hellmann-Feynman forces derived from ab initio calculations. The DFT ab initio codes, such as VASP or Wien2k provide tools to derive complete sets of such atomic forces. The harmonic phonon properties of bulk crystals, with or without defects,
surfaces, interfaces and similar systems can be calculated with the use of this method. Furthermore, the quasiharmonic approximation allows to treat the mentioned systems at finite temperature, which is a necessary step for extending DFT results to describe the systems in the complete manner.