# Ultrafast Umklapp-assisted electron-phonon cooling in magic-angle twisted bilayer graphene

https://mdr.nims.go.jp/datasets/9b7a774c-a712-4dbd-8e35-3f42aa0c534b

## File

- [sciadv.adj1361.pdf](https://mdr.nims.go.jp/filesets/cf5f88db-1b67-491d-8942-df7e990b11f7/download) ([Detail](https://mdr.nims.go.jp/filesets/cf5f88db-1b67-491d-8942-df7e990b11f7.md))

## Id

9b7a774c-a712-4dbd-8e35-3f42aa0c534b

## Local identifier



## Visibility

open_to_public

## State

published

## Created at

2025-02-18T01:41:29.540805Z

## Updated at

2025-02-23T13:46:44.499384Z

## Published at

2025-02-23T13:46:44.603227Z

## Doi



## First published url

https://doi.org/10.1126/sciadv.adj1361

## Date published

2024-02-09

## Recorded date published

2024-2-9

## Resource type

journal_article

## Manuscript type

vor

## Collection



## Title

- title: Ultrafast Umklapp-assisted electron-phonon cooling in magic-angle twisted
    bilayer graphene
  title_type: original
  lang: en

## Description

- description: 'Scattering between particles represents a crucial class of microscopic
    physical processes that govern transport properties and excited-state relaxation
    phenomena, among others. In crystals, as well as normal scattering, the discrete
    translation symmetry allows Umklapp scatter- ing events that do not conserve momentum.
    Phonon-phonon Umklapp scattering is a ubiquitous process that governs the thermal
    conductiv- ity of semiconductors and insulators, while electron-electron Umklapp
    scattering is only observed in ultraclean systems, usually at low temper- atures.
    In contrast, Umklapp scattering between electrons and phonons has not been demonstrated
    experimentally. Here we reveal the occurrence of electron-phonon Umklapp scattering
    in twisted bilayer graphene near the magic angle using time- and frequency-resolved
    photocurrent mea- surements. In magic-angle twisted bilayer graphene, a dramatic
    speedup of hot carrier cooling occurs: the cooling time is a few picoseconds from
    room temperature down to 5 K, where in pristine graphene coupling to acoustic
    phonons takes nanoseconds. Our theoretical calculations show that this ultrafast
    cooling is the result of the formation of a super- lattice with low-energy moir
    ́e phonons, spatially compressed electronic Wannier orbitals, and a reduced superlattice
    Brillouin zone, enabling Umklapp scattering and thus overcoming electron-phonon
    momentum mismatch. These results demonstrate the ability to engineer electron-
    phonon coupling in twistronic systems, and could contribute to the fundamental
    understanding of their transport properties, while enabling applications in thermal
    management and ultrafast photodetection.'
  description_type: abstract
  lang: und

## Creator

- name: Jake Dudley Mehew
  role: author
- name: Rafael Luque Merino
  role: author
- name: Hiroaki Ishizuka
  role: author
- name: Alexander Block
  role: author
- name: Jaime Díez Mérida
  role: author
- name: Andrés Díez Carlón
  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: Leonid S. Levitov
  role: author
- name: Dmitri K. Efetov
  role: author
- name: Klaas-Jan Tielrooij
  role: author

## Contact agent



## Publisher

organization: American Association for the Advancement of Science (AAAS)

## Managing organization



## Keyword

- subject: Electron-phonon interactions
  schema: not_defined
- subject: twisted bilayer graphene
  schema: not_defined
- subject: hot-electron cooling
  schema: not_defined

## Rights

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

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## Data origin



## Embargo



## Journal

- title: Science Advances
  issn: '23752548'
  volume: '10'
  issue: '6'
  article_number: eadj1361

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## Fileset

- id: cf5f88db-1b67-491d-8942-df7e990b11f7
  filename: sciadv.adj1361.pdf
  content_type: application/pdf
  size: 1423485
  md5: c41a94d41118302ff9bd507e97f93e2c

## Thumbnail

fileset_id: cf5f88db-1b67-491d-8942-df7e990b11f7
filename: sciadv.adj1361.pdf