Control of Subband Energies via Interlayer Twisting in an Artificially Stacked WSe₂ Bilayer

Tuning the electronic structure of artificially stacked bilayer crystals using their twist angle has attracted a significant amount of interest. In this study, resonant tunneling spectroscopy was performed on trilayer WSe₂/h-BN/twisted bilayer (tBL) WSe₂ devices with a wide range of twist angles (θ_BL) of tBL WSe₂, from 0° to 34°. We observed two resonant tunneling peaks, identified as the first and second lowest hole subbands at the valence band Γ point of tBL WSe₂. The subband separation, which directly measured the interlayer coupling strength, was tuned by ∼0.1 eV as θ_BL increased toward 6° and remained nearly constant for larger θ_BL values. The θ_BL dependence was attributed to the emergence of a stable W/Se (Se/W) stacking domain in the small θ_BL region, owing to the atomic reconstruction of the moiré lattice in tBL WSe₂. Our findings demonstrate that the twist-controlled subband energies in tBL WSe₂ are predominantly determined by local atomic reconstruction.