TY - JOUR
T1 - Broken mirror symmetry in excitonic response of reconstructed domains in twisted MoSe2/MoSe2 bilayers
AU - Sung, J.
AU - Zhou, You
AU - Scuri, Giovanni
AU - Zolyomi, Viktor
AU - Anderson, Trond I.
AU - Yoo, Hyobin
AU - Wild, Dominik S.
AU - Joe, Andrew Y.
AU - Gelly, Ryan J.
AU - Heo, Hoseok
AU - Magorrian, Samuel
AU - Bérubé, Damien
AU - Mier Valdivia, Andres M.
AU - Taniguchi, Takashi
AU - Watanabe, Kenji
AU - Lukin, Mikhail D.
AU - Kim, Philip
AU - Fal'ko, Vladimir
AU - Park, Hongkun
PY - 2020/6/3
Y1 - 2020/6/3
N2 - Van der Waals heterostructures obtained via stacking and twisting have been used to create moiré superlattices1, enabling new optical and electronic properties in solid-state systems. Moiré lattices in twisted bilayers of transition metal dichalcogenides (TMDs) result in exciton trapping2-5, host Mott insulating and superconducting states6, and act as unique Hubbard systems7-9 whose correlated electronic states can be detected and manipulated optically. Structurally, these twisted heterostructures feature atomic reconstruction and domain formation10-14. However, due to the nanoscale sizes of moiré domains, the effects of atomic reconstruction on the electronic and excitonic properties could not be systematically investigated. Here, we use near 0o twist angle MoSe2/MoSe2 bilayers with large rhombohedral AB/BA domains15 to directly probe excitonic properties of individual domains with far-field optics. We show that this system features broken mirror/inversion symmetry, with the AB and BA domains supporting interlayer excitons with out-of-plane electric dipole moments in opposite directions. The dipole orientation of ground-state -K interlayer excitons can be flipped with electric fields, while higher-energy K-K interlayer excitons undergo field-asymmetric hybridization with intralayer K-K excitons. Our study reveals the impact of crystal symmetry on TMD excitons and points to new avenues for realizing topologically nontrivial systems16,17, exotic metasurfaces18, collective excitonic phases19, and quantum emitter arrays20,21 via domain-pattern engineering.
AB - Van der Waals heterostructures obtained via stacking and twisting have been used to create moiré superlattices1, enabling new optical and electronic properties in solid-state systems. Moiré lattices in twisted bilayers of transition metal dichalcogenides (TMDs) result in exciton trapping2-5, host Mott insulating and superconducting states6, and act as unique Hubbard systems7-9 whose correlated electronic states can be detected and manipulated optically. Structurally, these twisted heterostructures feature atomic reconstruction and domain formation10-14. However, due to the nanoscale sizes of moiré domains, the effects of atomic reconstruction on the electronic and excitonic properties could not be systematically investigated. Here, we use near 0o twist angle MoSe2/MoSe2 bilayers with large rhombohedral AB/BA domains15 to directly probe excitonic properties of individual domains with far-field optics. We show that this system features broken mirror/inversion symmetry, with the AB and BA domains supporting interlayer excitons with out-of-plane electric dipole moments in opposite directions. The dipole orientation of ground-state -K interlayer excitons can be flipped with electric fields, while higher-energy K-K interlayer excitons undergo field-asymmetric hybridization with intralayer K-K excitons. Our study reveals the impact of crystal symmetry on TMD excitons and points to new avenues for realizing topologically nontrivial systems16,17, exotic metasurfaces18, collective excitonic phases19, and quantum emitter arrays20,21 via domain-pattern engineering.
M3 - Article
SN - 1748-3387
JO - Nature Nanotechnology
JF - Nature Nanotechnology
ER -