Every-other-layer Dipolar Excitons in a Spin-Valley locked Superlattice

Abstract

Monolayer semiconducting transition metal dichalcogenides possess broken inversion symmetry and strong spin-orbit coupling, which leads to unique spin-valley locking effect. In 2H stacked pristine multilayers, the spin-valley locking yields an electronic superlattice structure, where alternating layers correspond to barrier and quantum well respectively, conditioned on the spin-valley indices. Here, we show that the spin-valley locked superlattice hosts a new kind of dipolar excitons with the electron and hole constituents separated in an every-other-layer configuration, i.e., either in two even or two odd layers. Such excitons become optically bright via hybridization with intralayer excitons, displaying multiple anti-crossing patterns in optical reflection spectrum as the dipolar exciton is tuned through the intralayer resonance by electric field. The reflectance spectra also reveal an excited state orbital of the every-other-layer exciton, pointing to a sizable binding energy in the same order of magnitude as the intralayer exciton. As layer thickness increases, the dipolar exciton can form one-dimensional Bose-Hubbard chain displaying a layer number dependent fine-structures in the reflectance spectra. Our work reveals a distinct valleytronic superlattice with highly tunable dipolar excitons for exploring light-matter interactions.

References in corpus (3)

• Valley polarization in MoS2 monolayers by optical pumping
• Probing the spin-polarized electronic band structure in monolayer transition metal dichalcogenides by optical spectroscopy
• Exciton-polaritons in multilayer WSe${}_2$ in a planar microcavity

Cited by in corpus (8)

• Highly Tunable Ground and Excited State Excitonic Dipoles in Multilayer 2H-MoSe${}_2$
• Bright dipolar excitons in twisted black phosphorus homostructures
• Signatures of electric field and layer separation effects on the spin-valley physics of MoSe${}_2$/WSe${}_2$ heterobilayers: from energy bands to dipolar excitons
• Exciton Superposition across Moiré States in a Semiconducting Moiré Superlattice
• Tuning flat bands by interlayer interaction, spin-orbital coupling, and external fields in twisted homotrilayer MoS${}_2$
• Quadrupolar and Dipolar Excitons in Bilayer 2$H$-MoSe${}_2$
• Strong Correlation Driven Quadrupolar to Dipolar Exciton Transitions in a Trilayer Moiré Superlattice
• Rydberg series of intralayer K-excitons in WSe${}_2$ multilayers