Collective charge excitations between moiré-minibands in twisted WSe2 bilayers from resonant inelastic light scattering

Abstract: We establish low-temperature resonant inelastic light scattering (RILS) spectroscopy as a tool to probe the formation of a series of moir\'e-bands in twisted WSe_{2} bilayers by accessing collective intermoir\'e-band excitations (IMBE). We observe resonances in RILS spectra at energies in agreement with inter-moir\'e band transitions obtained from an ab-initio based continuum model. Transitions between the first and second inter-moir\'e band for a twist angle of about 8{\deg} are reported and between first and second, third and higher bands for a twist of about 3{\deg}. The signatures from IMBE for the latter highlight a strong departure from parabolic bands with flat minibands exhibiting very high density of states in accord with theory. These observations allow to quantify the transition energies at the K-point where the states relevant for correlation physics are hosted.