Fatemeh Haddadi^1*, QuanSheng Wu^2*, Alex J. Kruchkov^3*, Oleg V. Yazyev^2*

1 Institute of Physics, École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland

2 Institute of Physics, École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland and National Centre for Computational Design and Discovery of Novel Materials (MARVEL), École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland

3 Department of Physics, Harvard University, Cambridge, Massachusetts 02138, United States

* Corresponding authors emails: fatemeh.haddadi@epfl.ch, quansheng.wu@epfl.ch, akruchkov@g.harvard.edu, oleg.yazyev@epfl.ch

DOI10.24435/materialscloud:2020.0047/v1 [version v1]

Publication date: Apr 29, 2020

How to cite this record

Fatemeh Haddadi, QuanSheng Wu, Alex J. Kruchkov, Oleg V. Yazyev, Moiré Flat Bands in Twisted Double Bilayer Graphene, Materials Cloud Archive 2020.0047/v1 (2020), doi: 10.24435/materialscloud:2020.0047/v1.

Description

We investigate twisted double bilayer graphene (TDBG), a four-layer system composed of two AB-stacked graphene bilayers rotated with respect to each other by a small angle. Our ab-initio band structure calculations reveal a considerable energy gap at the charge point neutrality that we assign to the intrinsic symmetric polarization (ISP). We then introduce the ISP effect into the tight-binding parameterization and perform calculations on TDBG models that include lattice relaxation effects down to very small twist angles. We identify a narrow region around the magic angle θ*= 1.3° characterized by a manifold of remarkably flat bands gapped out from other states even without external electric fields. To understand the fundamental origin of the magic angle in TDBG, we construct a continuum model that points to a hidden mathematical link to the twisted bilayer graphene (TBG) model, thus indicating that the band flattening is a fundamental feature of TDBG, and is not a result of external fields.

Materials Cloud sections using this data

Files

File name	Size	Description
TDBG_TBISP.tar.gz MD5md5:4203914f703205f9c78d855c384b7efd	571.0 MiB	WannierTools inputs files for the tight-binding bandstructure calculations of the rigid and relaxed models of TDBG characterized by different twist angles in the presence of the intrinsic symmetric polarization.
readme.txt MD5md5:6be147077083c7f36e37ee31917f4e03	1.7 KiB	readme.txt containing detailed description of the dataset folder

License

Files and data are licensed under the terms of the following license: Creative Commons Attribution 4.0 International.
Metadata, except for email addresses, are licensed under the Creative Commons Attribution Share-Alike 4.0 International license.

External references

Keywords

MARVEL/DD6 EPFL SNSF Continuum model Twisted double bilayer graphene Tight-Binding model WannierTools Magic angle Flat bands Moiré superlattice