Description
In this talk I will discuss the theory of the quantum twisting microscope (QTM), covering both elastic and inelastic tunneling spectroscopy. Elastic tunneling spectroscopy probes electronic dispersions, which will be illustrated for both normal-conducting and superconducting systems. Inelastic tunneling spectroscopy probes collective-mode dispersions. Based on a experiment-theory collaboration, I will discuss the theory of QTM measurements of phonon dispersions and electron-phonon coupling strengths. Extraction of the electron-phonon couplings - of interest in the context of superconductivity in magic angle twisted bilayer graphene - requires careful analysis of various contributing inelastic tunneling processes. Phonon spectroscopy will be contrasted with a theoretical analysis of plasmon spectroscopy in QTM measurements. Unlike phonons, plasmons of moire systems are expected to be stongly affected by the interlayer coupling, making them a complementary case study of QTM spectroscopies of collective modes.
