Weak localization on moiré superlattice in twisted double bilayer graphene

Abstract

Negative magnetoresistance owing to weak localization (WL) was investigated in twisted double bilayer graphene (TDBG) as a function of the twist angle. The ratio of the intervalley scattering time to the intravalley scattering time, estimated using the WL formula for bilayer graphene, tended to decrease as the twist angle increased. This feature is qualitatively explained by the enhancement of intervalley scattering due to the reduction of the intervalley distance in the moiré Brillouin zone (BZ). This indicates that WL in the TDBG occurs with the reconstructed BZ and originates from the scattering process owing to the disorder in moiré superlattice.

Gate-controlled localization to delocalization transition of flat band wavefunction in twisted monolayer–bilayer graphene

“…Interestingly, the spatial delocalization of flat bands has already been reported in the STM experiments and transport measurements of tDBG. [22][23][24] High Phenomenologically, tMBG can be viewed as the transition state from TBG to tDBG. It seems naturally that tMBG system would host electronic structures similar both with TBG and tDBG.…”