We are looking for a highly motivated Ph.D. student with a great interest in experimental basic research in the field of ultrafast nanoscience and participation in university teaching as part of her*his doctorate. The position is based at TU Berlin with research activities at the Fritz Haber Institute.
Information on how to apply can be found here.

It has been reported that hot carriers have exceptionally long lifetimes in lead halide perovskites. This would have direct implications for applications, but the effect remains disputed and the mechanisms debated due to a lack of experimental studies providing direct evidence. Slow hot-carrier cooling of several picoseconds has been attributed to either polaron formation or a hot-phonon bottleneck effect at high excited carrier densities. We performed an ultrafast electron diffraction study to directly measure the sub-picosecond lattice dynamics of weakly confined CsPbBr3 nanocrystals following above-gap photoexcitation. While we do not observe signatures of a hot-phonon bottleneck lasting several picoseconds, the data reveal exciton-induced structural distortions.
Full paper: Seiler et al., ACS Nano 17, 1979 (2023).

The electronic band structure and crystal structure are the two complementary identifiers of solid-state materials. To cope with the growing size and scale of photoemission data, we developed a data analytics pipeline including probabilistic machine learning and the associated data processing, optimization, and evaluation methods for band-structure reconstruction, leveraging theoretical calculations. The pipeline reconstructs all 14 valence bands of a semiconductor and shows excellent performance on benchmarks and other materials datasets. The reconstruction uncovers previously inaccessible momentum-space structural information on both global and local scales while realizing a path toward integration with materials science databases.
Full story: Xian et al., Nature Comp. Sci. 3, 101 (2023).