Twisted 1T TaS2 bilayers by lithiation exfoliation

Abstract

We report twisted 1T TaS₂ bilayers synthesized by a lithiation exfoliation method. Atomic-scale observations reveal the existence of eight twist commensurate configurations from over 50 1T TaS₂ bilayer samples in the twist angle range from 0° to 30° in which commensurate atomic configurations can be distinguished by scanning transmission electron microscopy. The limited number of twist angles, rather than random ones, indicates that there are energetically favorite twist angles in the naturally formed bilayers. Together with the interlayer distance measurements, the formation of the bilayer twist configurations is anticipated to be regulated by the stacking energy in the charge-density-wave system through interlayer van der Waals interactions. The findings of this work may pave a new way to fabricate twisted bilayer TMDs for exploring exotic properties from additional moiré periodicity.