Correlated materials show a variety of electronic properties including collective excitations beyond a single particle description. The material’s rich phase diagrams - of interest to fundamental research and technological applications alike - keep challenging our theoretical understanding of the intricate interplay of charge, spin, orbital, and lattice degrees of freedom.
Among the various tools for materials simulation Density Functional Theory has proven to be the most versatile scheme and remains the working horse in the field. However, it shows some severe shortcomings when localized orbitals are present. To cure this deficiency different schemes have been proposed such as DFT+U, more sophisticated Hybrid Functionals or the combination of DFT with more generic many-body methods like dynamical mean-field theory.
The workshop intends to bring together a group of leading theoretical and computational physicists in the field of correlated materials to discuss the main challenges of today's state-of-the-art ab-initio calculations, the strengths and weaknesses of different methodologies and to explore the possibilities to integrate different numerical approaches into efficient and reliable computational tools.
This discussion on new developments of the numerical ab-initio tools will be based on the examples of topical materials. The aim of the workshop is to address the following topics:
- Heterostructures and Interfaces: Are our computational methods predictive for correlated heterostructures? And can we guide experiment towards synthesizing functional heterostructures?
- Bad Metals: How does the concept of Hund's correlations change when going from models to real materials?
- Iridates and Topological Phases: How to deal with spin-orbit coupling in strongly interacting systems? Can we calculate reliably topological invariants?
- Thermoelectricity: Can we separate the effects of electronic correlations from pure band-structure effects on the thermopower?
- Multiferroicity: Can we find a design strategy to optimise the critical temperature and to enable strong electronic correlations to enhance ferroelectricity?
- Superconductivity: Can we use Eliashberg-Migdal theory to estimate Tc of correlated materials? Can superconductivity be included at an ab-initio level in "correlated" calculations to calculate superconducting gap symmetries?
- Calculations beyond the local DMFT approximation: How far are we from using the diagrammatic extensions to DMFT in ab-initio calculations?
- Efficient DMFT Solvers and interaction parameters: Can we control the sign-problem in CTQMC calculations due to local hybridizations well enough to get high-quality results? Are other solvers (ED,...) reliable enough to make electronic structure calculations based on DMFT? What about the tools to calculate interaction parameters?
- Total energies and structure prediction: Can we calculate efficiently forces for correlated materials for structure predictions?
We intend to have one focus session per day devoted to one of the three above listed topics with the workshop ending in 3 days. These focus sessions will start with key-note talks of one hour length to summarise the current status of the field and they will be followed by more focused contributions in the respective field. In order to leave a sufficient amount of time for discussions, we plan to have not more than six participant talks per day.