Twisted transition metal dichalcogenides(TMDs)homo-bilayers host unique quantum properties,which can be tuned by interlayer twist angleθ.However,the systematic evolution of their typical electronic properties with re...Twisted transition metal dichalcogenides(TMDs)homo-bilayers host unique quantum properties,which can be tuned by interlayer twist angleθ.However,the systematic evolution of their typical electronic properties with respect to the twist angleθ,which is crucial for identifying the“special angle”analogous to the“magic angle”of twisted bilayer graphene in correlation physics studies,remains incompletely understood.Here,via scanning tunneling microscopy(STM)and spectroscopy(STS),we investigate the variation of the moirépotential,flat band,and layer polarization characteristics across a wide range of twist angleθin twisted bilayer MoS_(2)(TB-MoS_(2)).The moirépotential of the valence band exhibits a non-monotonic variation withθ,peaking at a maximum value up to 204 me Vatθ~1.7°.Concurrently,at the sameθ,the bandwidth of the flat band at theΓ_(V)point of the valence band attains its minimum,precisely signifying the“special angle”θ_(c)~1.7°in TB-MoS_(2).Interestingly,layer polarization in the moirésuperlattice is spatially visualized through the distribution of local density of states(LDOS)at the energies of bothΓ_(V)and K_(V)points of the valence band,where the polarization degree at theΓ_(V)point demonstrates a close dependency onθ.Our findings deepen understanding of twist-angle effect in TMDs,advancing both fundamental physics and practical application.展开更多
基金supported by the National Key R&D Program of China(Grant Nos.2022YFA1204700,and 2022YFA1204300)the National Natural Science Foundation of China(Grant Nos.12104144,52221001,and62090035)the Key Research and Development Plan of Hunan Province(Grant No.2023GK2012)。
文摘Twisted transition metal dichalcogenides(TMDs)homo-bilayers host unique quantum properties,which can be tuned by interlayer twist angleθ.However,the systematic evolution of their typical electronic properties with respect to the twist angleθ,which is crucial for identifying the“special angle”analogous to the“magic angle”of twisted bilayer graphene in correlation physics studies,remains incompletely understood.Here,via scanning tunneling microscopy(STM)and spectroscopy(STS),we investigate the variation of the moirépotential,flat band,and layer polarization characteristics across a wide range of twist angleθin twisted bilayer MoS_(2)(TB-MoS_(2)).The moirépotential of the valence band exhibits a non-monotonic variation withθ,peaking at a maximum value up to 204 me Vatθ~1.7°.Concurrently,at the sameθ,the bandwidth of the flat band at theΓ_(V)point of the valence band attains its minimum,precisely signifying the“special angle”θ_(c)~1.7°in TB-MoS_(2).Interestingly,layer polarization in the moirésuperlattice is spatially visualized through the distribution of local density of states(LDOS)at the energies of bothΓ_(V)and K_(V)points of the valence band,where the polarization degree at theΓ_(V)point demonstrates a close dependency onθ.Our findings deepen understanding of twist-angle effect in TMDs,advancing both fundamental physics and practical application.
