Control of Subband Energies via Interlayer Twisting in an Artificially Stacked WSe 2 Bilayer

• Published in: Nano letters 2024-10, Vol.24 (39), p.12211-12217
• Main Authors: Kinoshita, Kei, Moriya, Rai, Okazaki, Shota, Onodera, Momoko, Zhang, Yijin, Watanabe, Kenji, Taniguchi, Takashi, Sasagawa, Takao, Machida, Tomoki
• Format: Article
• Language: English
• ISSN: 1530-6984; 1530-6992
• DOI: 10.1021/acs.nanolett.4c03289

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 WSe / -BN/twisted bilayer (tBL) WSe devices with a wide range of twist angles (θ ) of tBL WSe , 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 WSe . The subband separation, which directly measured the interlayer coupling strength, was tuned by ∼0.1 eV as θ increased toward 6° and remained nearly constant for larger θ values. The θ dependence was attributed to the emergence of a stable W/Se (Se/W) stacking domain in the small θ region, owing to the atomic reconstruction of the moiré lattice in tBL WSe . Our findings demonstrate that the twist-controlled subband energies in tBL WSe are predominantly determined by local atomic reconstruction.