# Observation of ~100% valley-coherent excitons in monolayer MoS2 through giant enhancement of valley coherence time

https://mdr.nims.go.jp/datasets/846e2b37-88bd-4370-9f63-19d1be8fb77a

## File

- [s41377-023-01220-4.pdf](https://mdr.nims.go.jp/filesets/dc02518f-b3d5-46ca-b7ee-783c663e8ebd/download) ([Detail](https://mdr.nims.go.jp/filesets/dc02518f-b3d5-46ca-b7ee-783c663e8ebd.md))

## Id

846e2b37-88bd-4370-9f63-19d1be8fb77a

## Local identifier



## Visibility

open_to_public

## State

published

## Created at

2025-02-14T04:03:54.745155Z

## Updated at

2025-02-14T07:30:25.335482Z

## Published at

2025-02-14T07:30:25.438457Z

## Doi



## First published url

https://doi.org/10.1038/s41377-023-01220-4

## Date published

2023-07-13

## Recorded date published



## Resource type

journal_article

## Manuscript type

vor

## Collection



## Title

- title: Observation of ~100% valley-coherent excitons in monolayer MoS2 through giant
    enhancement of valley coherence time
  title_type: original
  lang: en

## Description

- description: In monolayer transition metal dichalcogenide semiconductors, valley
    coherence degrades rapidly due to a combination of fast scattering and inter-valley
    exchange interaction. This leads to a sub-picosecond valley coherence time, making
    coherent manipulation of exciton a highly formidable task. Using monolayer MoS2
    sandwiched between top and bottom graphene, here we demonstrate perfect valley
    coherence by observing 100% degree of linear polarization of excitons in steady
    state photoluminescence. This is achieved in this unique design through a combined
    effect of (a) suppression in exchange interaction due to enhanced dielectric screening,
    (b) reduction in exciton lifetime due to a fast inter-layer transfer to graphene,
    and (c) operating in the motional narrowing regime. We disentangle the role of
    the key parameters affecting valley coherence by using a combination of calculation
    (solutions of Bethe-Salpeter and steady-state Maialle-Silva-Sham equations) and
    choice of systematic design of experiments using four different stacks with varying
    screening and exciton lifetime. To the best of our knowledge, this is the first
    report in which the valley coherence timescale has been significantly enhanced
    beyond the exciton radiative lifetime in monolayer semiconductors.
  description_type: abstract
  lang: und

## Creator

- name: Garima Gupta
  role: author
- name: Kenji Watanabe
  role: author
  orcid: https://orcid.org/0000-0003-3701-8119
  organization: National Institute for Materials Science
  ror: https://ror.org/026v1ze26
- name: Takashi Taniguchi
  role: author
  orcid: https://orcid.org/0000-0002-1467-3105
  organization: National Institute for Materials Science
  ror: https://ror.org/026v1ze26
- name: Kausik Majumdar
  role: author

## Contact agent



## Publisher

organization: Springer Science and Business Media LLC

## Managing organization



## Keyword

- subject: Valley coherence
  schema: not_defined
- subject: monolayer MoS2
  schema: not_defined
- subject: photoluminescence
  schema: not_defined

## Rights

- identifier: https://creativecommons.org/licenses/by/4.0/

## Other identifier(s)



## Data origin

- data_origin_type: other

## Embargo



## Journal

- title: 'Light: Science & Applications'
  issn: '20477538'
  volume: '12'
  issue: '1'
  article_number: '173'

## Conference



## Related item



## Funding

- funder_name: DST | Science and Engineering Research Board

## Instrument



## Instrument operator



## Instrument managing organization



## Measurement method



## Specimen



## Chemical composition



## Structure for specimen



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## Fileset

- id: dc02518f-b3d5-46ca-b7ee-783c663e8ebd
  filename: s41377-023-01220-4.pdf
  content_type: application/pdf
  size: 1328342
  md5: 5d4b390e77eed2eed97cc165e4d7d7a3

## Thumbnail

fileset_id: dc02518f-b3d5-46ca-b7ee-783c663e8ebd
filename: s41377-023-01220-4.pdf