Electrically tunable Feshbach resonances in twisted bilayer semiconductors

Moire superlattices in transition metal dichalcogenide bilayers provide a platform for exploring strong correlations with optical spectroscopy. Despite the observation of rich Mott-Wigner physics stemming from an interplay between the periodic potential and Coulomb interactions, the absence of tunnel coupling-induced hybridization of electronic states has ensured a classical layer degree of freedom. We investigated a MoSe2 homobilayer structure where interlayer coherent tunneling allows for electric field-controlled manipulation and measurement of the ground-state hole-layer pseudospin. We observed an electrically tunable two-dimensional Feshbach resonance in exciton-hole scattering, which allowed us to control the strength of interactions between excitons and holes located in different layers. Our results may enable the realization of degenerate Bose-Fermi mixtures with tunable interactions.

Automated summary

In this study, Moire superlattices in transition metal dichalcogenide bilayers were used as a platform to explore strong correlations with optical spectroscopy. By investigating a MoSe2 homobilayer structure, the researchers demonstrated electric field-controlled manipulation of the ground-state hole-layer pseudospin, as well as the observation of an electrically tunable two-dimensional Feshbach resonance in exciton-hole scattering. These findings may pave the way for the realization of degenerate Bose-Fermi mixtures with tunable interactions.