### From Theory to Numbers

Whenever analytical approaches are not possible we employ numerical methods. In house developed codes are developed and mainly used for the simulations. Some of them have been demonstrated to parallelize almost ideally on tens of thousands of processor cores. These codes are also combined with open source or proprietary software packages, particularly for the ab initio part.

### Transverse Transport Phenomena

are unconventional responses in the sense that they are transverse to the external fields. Examples include Hall effects, Spin-Hall effects, or transverse thermoelectric effects (Nernst effect) etc. We have developed a linear-scaling approach to simulate such transverse transport on a large scale (millions of orbitals) which allows to have unprecedented insight into the underlying physics.

Further reading: Phys. Rev. Lett. 2013, Phys. Rev. B 2015

### General Linear Response Phenomena

Connected to the above research topic, we have developed a generalized approach to describe a large class of response functions in a recent work Phys. Rev. Lett. 2021.

### Ab Initio

The variety of materials need to be described on the ab initio level to simulate their specific properties. We use density functional theory and time-dependent density functional theory for the simulations of various electronic parameters and optical spectra. Molecular dynamics, many-body perturbation theory and wave function-based methods complete the set of approaches used.

### Ultrafast Dynamics, Transport and Localization

Transport phenomena from the femtosecond to the nanosecond timescale are being explored. We develop efficient linear-scaling approaches (order N) and implement them in our codes.

Further reading: EPL 2011, Phys. Rev. Lett. 2013, Nano Lett. 2013, 2D Mater 2014