Dear colleagues,
let me invite you to the next institute seminar tomorrow Thursday 18 June 2026 at 10:00 in Meeting room 101. This week presentation will be done by:
Dr. Otakar Frank
Department of Electrochemical Materials, J. Heyrovsky Institute of Physical Chemistry in Prague
(Nano)spectroscopic fingerprints of interactions in 2D materials
Abstract:
Common spectroscopic investigation of two-dimensional materials and their van der Waals (vdW) heterostructures mostly relies either on diffraction-limited micro-Raman or photoluminescence (PL). However, these methods do not properly capture local variations caused by, e.g., nanometre-sized heterogeneities stemming from contamination trapped between the layers or complex strain and charge patterns formed by strong out-of-plane interactions.
Tip-enhanced spectroscopy methods enable access to information on the local lattice deformation and also on the interaction between the individual layers composing the heterostructure. What may appear as peak splitting in micro-Raman or PL spectra of transition metal dichalcogenides (TMDC) on metal substrates or of vdW heterobilayers, can, in fact, often come from mixing up signals from various regions within the laser spot, including new or discretely shifted peaks. In other cases, however, peak splitting can indicate lifting the degeneracy of the phonon, due to, for example, uniaxial deformation. Spectroscopic fingerprints, both on micro- and nanoscale, of variously interacting vdW layers will be discussed, including TMDCs on metals and TMDC heterobilayers.
We look forward to seeing you.