Computational Modeling of Out-of-Equilibrium Dynamics and of Superconductivity

Dnr:

NAISS 2023/6-124

Type:

NAISS Medium Storage

Principal Investigator:

Peter Oppeneer

Affiliation:

Uppsala universitet

Start Date:

2023-07-01

End Date:

2024-07-01

Primary Classification:

10304: Condensed Matter Physics

Secondary Classification:

10302: Atom and Molecular Physics and Optics

Tertiary Classification:

10402: Physical Chemistry

Webpage:

- Centre Storage at NSC: 9000 GiB
- Klemming at PDC: 4000 GiB

Our work is placed in the area of computational condensed matter physics, where we perform frontline research in various field, such as ab-initio theory of superconductivity, theory for out-of-equilibrium dynamics, and theory for molecular spintronics. Our work is computational intensive and it requires substantial storage allocations.
More specific, we perform fully selfconsistent calculations of temperature-dependent superconductivity in real materials. To do this we have in the last years developed the Uppsala Superconductivity (UppSC) code, which is a full-bandwidth, multi-band, anisotropic Eliashberg code for selfconsistent calculations of unconventional superconductivity using full ab-initio input from DFT calculations. This code is worldwide unique. It can e.g. treat phonon-mediated pairing and spin-fluctuations-mediated Cooper pairing, as well as conventional and unconventional multiband superconductivity. Until recent fully ab-initio calculations of superconductivity have not been possible; we aim however at changing this situation. To perform these calculations we do need a substantial storage allocation.
Another area on which we are currently working is the ab-initio modeling of out-of-equilibrium dynamics to simulate ultrafast pump-probe experiments. Here we perform ab-initio calculations of the strongly enhanced electron and lattice dynamics that occur in solid-state systems upon excitation with an ultrashort laser pulse. To this end we have developed a theory for describing the out-of-equilibrium ultrafast relaxation dynamics, which is completely ab initio based and takes all non-equilibrium processes (e.g., electron-phonon, phonon-phonon interactions) into account. For the modeling we need to compute a number of quantities, such as phonon dispersions and lifetimes and wavevector and the mode dependent electron-phonon coupling.
A further area (not mentioned in the title) concerns state-of-the-art calculations to study the electronic structure, magnetic and structural properties of spin-bearing metal-organic materials (spin-crossover materials) and single molecule magnets. We are investigating the possible spin switching of metalorganic molecules on a metallic surface and in contact with a reagent (e.g., nitric oxide) in order to discover conditions under which the spin can be switched in a molecular electronic device. Another research direction here is the ab-initio molecular dynamics description and prediction of spin-crossover systems, invoking temperature effects through molecular dynamics simulations.
Notably, the scientific gain achieved by performing these calculations is enormous which emphasizes the strength of computational materials modeling.