Broken mirror symmetry in excitonic response of reconstructed domains in twisted MoSe 2 /MoSe 2 bilayers.

Autor: Sung J; Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA.; Department of Physics, Harvard University, Cambridge, MA, USA., Zhou Y; Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA.; Department of Physics, Harvard University, Cambridge, MA, USA., Scuri G; Department of Physics, Harvard University, Cambridge, MA, USA., Zólyomi V; National Graphene Institute, University of Manchester, Manchester, UK.; Hartree Centre, STFC Daresbury Laboratory, Daresbury, UK., Andersen TI; Department of Physics, Harvard University, Cambridge, MA, USA., Yoo H; Department of Physics, Harvard University, Cambridge, MA, USA.; Department of Physics, Sogang University, Seoul, Republic of Korea., Wild DS; Department of Physics, Harvard University, Cambridge, MA, USA., Joe AY; Department of Physics, Harvard University, Cambridge, MA, USA., Gelly RJ; Department of Physics, Harvard University, Cambridge, MA, USA., Heo H; Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA.; Department of Physics, Harvard University, Cambridge, MA, USA., Magorrian SJ; National Graphene Institute, University of Manchester, Manchester, UK., Bérubé D; Department of Physics, California Institute of Technology, Pasadena, CA, USA., Valdivia AMM; John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA., Taniguchi T; National Institute for Materials Science, Tsukuba, Japan., Watanabe K; National Institute for Materials Science, Tsukuba, Japan., Lukin MD; Department of Physics, Harvard University, Cambridge, MA, USA., Kim P; Department of Physics, Harvard University, Cambridge, MA, USA.; John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA., Fal'ko VI; National Graphene Institute, University of Manchester, Manchester, UK. Vladimir.Falko@manchester.ac.uk.; Henry Royce Institute for Advanced Materials, University of Manchester, Manchester, UK. Vladimir.Falko@manchester.ac.uk., Park H; Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA. Hongkun_Park@harvard.edu.; Department of Physics, Harvard University, Cambridge, MA, USA. Hongkun_Park@harvard.edu.
Jazyk: angličtina
Zdroj: Nature nanotechnology [Nat Nanotechnol] 2020 Sep; Vol. 15 (9), pp. 750-754. Date of Electronic Publication: 2020 Jul 13.
DOI: 10.1038/s41565-020-0728-z
Abstrakt: Van der Waals heterostructures obtained via stacking and twisting have been used to create moiré superlattices 1 , enabling new optical and electronic properties in solid-state systems. Moiré lattices in twisted bilayers of transition metal dichalcogenides (TMDs) result in exciton trapping 2-5 , host Mott insulating and superconducting states 6 and act as unique Hubbard systems 7-9 whose correlated electronic states can be detected and manipulated optically. Structurally, these twisted heterostructures feature atomic reconstruction and domain formation 10-14 . However, due to the nanoscale size of moiré domains, the effects of atomic reconstruction on the electronic and excitonic properties have not been systematically investigated. Here we use near-0°-twist-angle MoSe 2 /MoSe 2 bilayers with large rhombohedral AB/BA domains 15 to directly probe the 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 Γ-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 non-trivial systems 16,17 , exotic metasurfaces 18 , collective excitonic phases 19 and quantum emitter arrays 20,21 via domain-pattern engineering.
Databáze: MEDLINE
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