Coulomb-bound four- and five-particle intervalley states in an atomically-thin semiconductor

Shao Yu Chen, Thomas Goldstein, Takashi Taniguchi, Kenji Watanabe, Jun Yan

Research output: Contribution to journalArticleResearchpeer-review

33 Citations (Scopus)

Abstract

As hosts for tightly-bound electron-hole pairs carrying quantized angular momentum, atomically-thin semiconductors of transition metal dichalcogenides (TMDCs) provide an appealing platform for optically addressing the valley degree of freedom. In particular, the valleytronic properties of neutral and charged excitons in these systems have been widely investigated. Meanwhile, correlated quantum states involving more particles are still elusive and controversial despite recent efforts. Here, we present experimental evidence for four-particle biexcitons and five-particle exciton-trions in high-quality monolayer tungsten diselenide. Through charge doping, thermal activation, and magnetic-field tuning measurements, we determine that the biexciton and the exciton-trion are bound with respect to the bright exciton and the trion, respectively. Further, both the biexciton and the exciton-trion are intervalley complexes involving dark excitons, giving rise to emissions with large, negative valley polarization in contrast to that of the two-particle excitons. Our studies provide opportunities for building valleytronic quantum devices harnessing high-order TMDC excitations.

Original languageEnglish
Article number3717
Pages (from-to)1-8
Number of pages8
JournalNature Communications
Volume9
Issue number1
DOIs
Publication statusPublished - 1 Dec 2018
Externally publishedYes

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