Project A12: Structure and Phonons of Heteroepitaxial Stacks of Weakly Interacting 2D Materials and Molecular Layers

Principle Investigator: Prof. Dr. Stefan Tautz, Dr. Francois Bocquet, Prof. Dr. Christian Kumpf (Jülich, Peter Grünberg Institut)

Summary

We aim at understanding electronic states at the interface between different semiconducting low-dimensional materials (e.g., molecular crystals or transition metal dichalcogenides) or between such materials and a (noble) metal. Employing a combination of density-functional theory, van der Waals interaction, and many-body perturbation theory, all relevant physical mechanisms (chemical bonds, physisorption, electrostatic interaction, dielectric screening, image-potential effects, etc.) are correctly included. Challenges are given by, e.g. the role of material thickness or the spatial decay of interface states in the normal direction. In the lateral dimension, dispersive bands as well as local, non-dispersive states may occur, depending on the competition between interaction within each material and hybridization across the interface.

Project-Related Publications

1. T. Förster, P. Krüger, M. Rohlfing Two-dimensional topological phases and electronic spectrum of Bi₂Se₃ thin films from GW calculations Phys. Rev. B 92, 201404(R) (2015).
2. R. Schmidt, I. Niehues, R. Schneider, M. Drüppel, T. Deilmann, M. Rohlfing, S. Michaledis de Vasconcellos, A. Castellanos-Gomez, R. Bratschitsch Reversible uniaxial strain tuning in atomically thin WSe₂ 2D Materials 3, 021011 (2016).
3. T. Esat, B. Lechtenberg, T. Deilmann, C. Wagner, P. Krüger, R. Temirov, M. Rohlfing, F. B. Anders, F.S. Tautz A chemically driven quantum phase transition in a two-molecule Kondo system Nature Phys., doi: 10.1038/nphys3737 (2016).