3. Doped TMDs* & graphene: electronic structure and electron-phonon coupling

Ionic liquid gating is an effective and reliable technique to accumulate very large amounts of charge carriers at the liquid/solid interface of layered materials and it therefore constitutes a new way of charge doping. This technique has so far been explored mainly by transport measurements. The aim of this project is to capture the changes induced by the gating directly in the occupied electronic band structure by angle-resolved photon emission spectroscopy (ARPES) performed at a synchrotron beam line. This will add new information on how the electronic states change across the whole electronic phase diagram, particularly the superconducting dome of MoS2; the results will also allow to explore the changes of electron-phonon coupling and in Fermi velocity as a function of ionic liquid-induced doping. Once we have explored these two 2D solids we shall move on to other 2D solids that are also subject of study in project 1 above. Using a dedicated in-situ setup, in which the ionic liquid is repeatedly frozen and molten and then gated at different bias voltages just above its freezing temperature, allows determination of the dispersion curves for different carrier densities at the interface with high resolution, both in angle and in energy, to spectroscopically map the electronic phase diagram.

Team of supervising researchers: Petra Rudolf & Caspar van der Wal

PhD students: Giovanna Feraco