# Isospin competitions and valley polarized correlated insulators in twisted double bilayer graphene

https://mdr.nims.go.jp/datasets/78b128c1-2239-4fa8-98ae-7f6b3d5b1720

## File

- [s41467-022-30998-x.pdf](https://mdr.nims.go.jp/filesets/6a405d70-5c2a-44b4-ae2c-bcd70bce11eb/download) ([Detail](https://mdr.nims.go.jp/filesets/6a405d70-5c2a-44b4-ae2c-bcd70bce11eb.md))

## Id

78b128c1-2239-4fa8-98ae-7f6b3d5b1720

## Local identifier



## Visibility

open_to_public

## State

published

## Created at

2025-02-26T07:18:56.152952Z

## Updated at

2025-02-27T03:31:07.510726Z

## Published at

2025-02-27T03:31:07.637355Z

## Doi



## First published url

https://doi.org/10.1038/s41467-022-30998-x

## Date published

2022-06-07

## Recorded date published



## Resource type

journal_article

## Manuscript type

vor

## Collection



## Title

- title: Isospin competitions and valley polarized correlated insulators in twisted
    double bilayer graphene
  title_type: original
  lang: en

## Description

- description: New phase of matter usually emerges when a given symmetry breaks spontaneously,
    which can involve charge, spin, and valley degree of freedoms. Here, we report
    an observation of new correlated insulators evolved from spin polarized states
    to valley polarized states in AB-BA stacked twisted double bilayer graphene (TDBG).
    The transition of the isospin polarization is a result of the competition between
    spin and valley, driven by the displacement field (D). At a high field |D| > 0.7
    V/nm, we observe valley polarized correlated insulators with a big Zeeman g factor
    of ~10, both at v = 2 in the moiré conduction band and more surprisingly at v
    = -2 in the moiré valence band. At a medium field |D| < 0.6 V/nm, by contrast,
    it is a conventional spin polarized correlated insulator at v = 2 and a featureless
    metal at v = -2. Moreover, we observe a valley polarized Chern insulator with
    C = 2 emanating at v = 2 in the electron side and a valley polarized Fermi surface
    around v = -2 in the hole side. The valley Chern insulator with C = 2 is evident
    from a well quantized Hall conductance plateau at 2e2/h and correspondingly a
    vanishing longitudinal component. The valley polarized Fermi surface is topologically
    trivial with C = 0, and it shows a series of quantized Landau levels with vLL
    = 0, ±1, ±2, ±3, ±4 and others. These observations are in good agreements with
    our band and topology calculations. Our results demonstrate a feasible way to
    realize isospin control and to obtain new phases of matter in TDBG by the displacement
    field, and might benefit other twisted or non-twisted multilayer systems.
  description_type: abstract
  lang: und

## Creator

- name: Le Liu
  role: author
- name: Shihao Zhang
  role: author
- name: Yanbang Chu
  role: author
- name: Cheng Shen
  role: author
- name: Yuan Huang
  role: author
- name: Yalong Yuan
  role: author
- name: Jinpeng Tian
  role: author
- name: Jian Tang
  role: author
- name: Yiru Ji
  role: author
- name: Rong Yang
  role: author
- name: Kenji Watanabe
  role: author
  orcid: https://orcid.org/0000-0003-3701-8119
  organization: National Institute for Materials Science
- name: Takashi Taniguchi
  role: author
  orcid: https://orcid.org/0000-0002-1467-3105
  organization: National Institute for Materials Science
- name: Dongxia Shi
  role: author
- name: Jianpeng Liu
  role: author
- name: Wei Yang
  role: author
- name: Guangyu Zhang
  role: author

## Contact agent



## Publisher

organization: Springer Science and Business Media LLC

## Managing organization



## Keyword

- subject: Symmetry break
  schema: not_defined
- subject: spin-polarized
  schema: not_defined
- subject: valley-polarized
  schema: not_defined

## Rights

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

## Other identifier(s)



## Data origin



## Embargo



## Journal

- title: Nature Communications
  issn: '20411723'
  volume: '13'
  issue: '1'
  article_number: '3292'

## Conference



## Related item



## Funding

- identifier: '61888102,11834017,1207441'
  funder_name: National Natural Science Foundation of China

## Instrument



## Instrument operator



## Instrument managing organization



## Measurement method



## Specimen



## Chemical composition



## Structure for specimen



## Structural feature for specimen



## Specific property for specimen



## Process for specimen treatment



## Computational method



## Energy level/transition state



## Software



## Custom property



## Fileset

- id: 6a405d70-5c2a-44b4-ae2c-bcd70bce11eb
  filename: s41467-022-30998-x.pdf
  content_type: application/pdf
  size: 3803716
  md5: ca050883a2ec92b83040c7de336be329

## Thumbnail

fileset_id: 6a405d70-5c2a-44b4-ae2c-bcd70bce11eb
filename: s41467-022-30998-x.pdf