Projects

       
We always welcome applications from motivated students and researchers of all levels. Exemplary projects are listed below. Please contact Jan Wilhelm for further details.

Development of large-scale electronic structure methods

The main focus of the group is to develop large-scale electronic structure methods that are capable of dealing with hundreds to thousands of atoms in the simulation. Such large-scale electronic structure problems routinely arise when modeling liquids, disordered materials or interfaces. As an example, you see below a moiré structure of two hexagonal layers (blue and orange). Moiré structures feature very interesting physical properties, from superconductivity [3] to strong band gap variations [4]. The unit cell of moiré structures is large, see below the black box as an example which contains roughly 500 atoms. Treating such a large unit cell is already a challenge for standard electronic structure methods.

      
We implement electronic structure methods in the open-source CP2K package [1,2]. CP2K uses Gaussian basis functions and can describe molecules as well as periodic systems. CP2K is optimized for massively parallel execution on the latest supercomputers and has a quickly growing user community in physics, chemistry and materials science.
     
The following projects are open in the field of large-scale electronic structure method development: 

• Laser pulses in time-dependent density functional theory (TDDFT) simulations

• Time-dependent Bethe-Salpeter equation for exciton dynamics simulations

• Pseudopotentials with spin-orbit coupling

• Machine learning of the Hartree potential from the density matrix to accelerate TDDFT simulations

References:

[1] See https://github.com/cp2k/cp2k and https://cp2k.org

[2] T. D. Kühne et al., CP2K: An electronic structure and molecular dynamics software package - Quickstep: Efficient and accurate electronic structure calculations, J. Chem. Phys. 152, 194103 (2020).

[3] Y. Cao et al., Unconventional superconductivity in magic-angle graphene superlattices, Nature 556, 43-50 (2018).

[4] Shabani et al., Deep moiré potentials in twisted transition metal dichalcogenide bilayers, Nat. Phys. 17, 720-725 (2021).

Topics for a Master thesis

Computational projects for analyzing ultrafast dynamics, bandgaps and energy levels are available: 

• Ultrafast dynamics and high-harmonic generation

• Bandgap modulation in moiré structures

• Energy levels of molecules with unpaired electrons

If you are interested in a Master thesis project, please contact Jan Wilhelm.