Valley phonons and exciton complexes in a monolayer semiconductor

The coupling between spin, charge, and lattice degrees of freedom plays an important role in a wide range of fundamental phenomena. Monolayer semiconducting transitional metal dichalcogenides have emerged as an outstanding platform for studying these coupling effects. Here, we report the observation...

Full description

Saved in:
Bibliographic Details
Published in:Nature communications 2020-01, Vol.11 (1), p.618-618, Article 618
Main Authors: He, Minhao, Rivera, Pasqual, Van Tuan, Dinh, Wilson, Nathan P., Yang, Min, Taniguchi, Takashi, Watanabe, Kenji, Yan, Jiaqiang, Mandrus, David G., Yu, Hongyi, Dery, Hanan, Yao, Wang, Xu, Xiaodong
Format: Article
Language:English
Subjects:
639/301/119/1000/1018
639/766/119/1000/1018
Brillouin zones
Corners
Coupling
Degrees of freedom
Electromagnetism
Electronics industry
Energy
Excitons
Humanities and Social Sciences
MATERIALS SCIENCE
Momentum
Monolayers
multidisciplinary
Phonons
Photoluminescence
Photons
Physics
Science
Science (multidisciplinary)
Trions
Two-dimensional materials
Valleys
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:The coupling between spin, charge, and lattice degrees of freedom plays an important role in a wide range of fundamental phenomena. Monolayer semiconducting transitional metal dichalcogenides have emerged as an outstanding platform for studying these coupling effects. Here, we report the observation of multiple valley phonons – phonons with momentum vectors pointing to the corners of the hexagonal Brillouin zone – and the resulting exciton complexes in the monolayer semiconductor WSe 2 . We find that these valley phonons lead to efficient intervalley scattering of quasi particles in both exciton formation and relaxation. This leads to a series of photoluminescence peaks as valley phonon replicas of dark trions. Using identified valley phonons, we also uncover an intervalley exciton near charge neutrality. Our work not only identifies a number of previously unknown 2D excitonic species, but also shows that monolayer WSe 2 is a prime candidate for studying interactions between spin, pseudospin, and zone-edge phonons. In monolayer semiconductors phonons with momentum vectors pointing to the corners of the hexagonal Brillouin zone couple strongly to carriers’ spin and valley degree of freedom. Here, the authors report the observation of multiple valley phonons and the resulting exciton complexes in the monolayer semiconductor WSe 2 .
ISSN:2041-1723
2041-1723
DOI:10.1038/s41467-020-14472-0