Terahertz and DC nonlinear transport in twisted graphene and van der Waals heterostructures

• Applicant: Professor Dr. Jörg Wunderlich
• Subject Area: Experimental Condensed Matter Physics
• Term: since 2026
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 572024380

Our research project focuses on nonlinear transport phenomena in novel two-dimensional Van der Waals quantum materials in an exceptionally large energy range. This range extends from quasi-direct current to optical frequencies and includes microwave, terahertz, and mid-infrared spectra. The focus is on nonlinear transport phenomena in two-dimensional twisted bilayer graphene (tBLG) and in bilayer heterostructures consisting of transition metal dichalcogenide (TMDC) and graphene. In particular, we want to combine and compare nonlinear transport measurements with polarized THz/IR radiation and with electric, quasi-direct current DC fields at de facto zero frequencies. In order to also investigate symmetry breaking effects due to crystal defects and topological domain walls, our experiments will not only be carried out with diffraction-limited far-field THz/IR radiation on macroscopic length scales, but also with scattering-type near-field scanning microscopy, which enables the generation of photocurrents on nanoscopic length scales. Since there have been only a few studies on nonlinear transport in van der Waals 2D materials, our planned experimental and theoretical investigations are an important and challenging task that will contribute to elucidating many fundamental properties of Van der Waals quantum materials.

• DFG Programme: Research Grants
• Co-Investigator: Professor Dr. Sergey Ganichev