The Soft Condensed Matter group (SCM, Utrecht University, The Netherlands) is looking for two PhD students (m/f) with a strong interest in atomistic simulation and nanoscience, for a research program entitled ‘Atomic Scale Understanding of Cation Exchange in Nanocrystals’. Nanocrystals are small semiconductor crystals (CdSe, PbSe) with a size of a few nanometers. Their physical properties (optical, opto-electronic) can be changed and manipulated in a spectacular way by a process called cation exchange. For example, Pb atoms in PbSe nanocrystals can be partly replaced by Cd atoms, so that PbSe/CdSe core/shell nanocrystals are formed.

Although the experimental creation of these intricate nanocrystals is advancing and producing impressive results, the theoretical understanding of that process is at its infancy.



The PhD students will contribute to this cutting-edge research by performing relevant calculations and simulations. One PhD student will investigate the most fundamental aspects of this process, and use quantum mechanical density functional theory (DFT) calculations to investigate the energies and electronic state of defects, migrating atoms, and nanoscale interfaces.

The second PhD student will work at a larger time scale, and perform molecular dynamics (MD) and kinetic Monte Carlo (kMC) simulations to investigate the kinetics (reconstuctions, shape changes) of complete nanostructures. The outcome of the simulations will be compared directly with experimental data obtained from high-resolution transmission electron microscopy (HRTEM). There is opportunity also to be involved in the experimental part of the program.