Evolution of QTM tunneling spectra with doping in twisted bilayer graphene

Determine the evolution of the quantum twisting microscope (QTM) differential conductance dI/dV(V, θ) in twisted bilayer graphene as the carrier doping is varied, explicitly accounting for the doping-induced changes in the band structure, the particle–hole continuum, and the plasmon dispersion and damping, in order to characterize how these modifications affect plasmon-assisted tunneling features across the moiré Brillouin zone.

Background

The paper develops a theory and numerical framework for plasmon-assisted inelastic tunneling spectroscopy using a quantum twisting microscope (QTM), focusing on charge-neutral twisted bilayer graphene (TBG). It analyzes signatures of plasmons both at low bias (plasmon satellites near the flat bands) and at higher bias (onset features associated with tunneling into remote bands) and discusses the role of screening environments.

In the Discussion, the authors note that doping substantially modifies the flat-band bandwidth via Hartree potentials, broadens the particle–hole continuum, and alters plasmon characteristics (e.g., dispersion and damping). They suggest that these changes could significantly affect the QTM tunneling spectra but leave the detailed exploration of doping dependence for future study.