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Atomistic Hartree theory of twisted double bilayer graphene near the magic angle

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Title: Atomistic Hartree theory of twisted double bilayer graphene near the magic angle
Authors: Cheung, CTS
Goodwin, ZAH
Vitale, V
Lischner, J
Mostofi, AA
Item Type: Journal Article
Abstract: Twisted double bilayer graphene (tDBLG) is a moiré material that has recently generated significant interest because of the observation of correlated phases near the magic angle. We carry out atomistic Hartree theory calculations to study the role of electron–electron interactions in the normal state of tDBLG. In contrast to twisted bilayer graphene, we find that such interactions do not result in significant doping-dependent deformations of the electronic band structure of tDBLG. However, interactions play an important role for the electronic structure in the presence of a perpendicular electric field as they screen the external field. Finally, we analyze the contribution of the Hartree potential to the crystal field, i.e. the on-site energy difference between the inner and outer layers. We find that the on-site energy obtained from Hartree theory has the same sign, but a smaller magnitude compared to previous studies in which the on-site energy was determined by fitting tight-binding results to ab initio density-functional theory (DFT) band structures. To understand this quantitative difference, we analyze the ab initio Kohn–Sham potential obtained from DFT and find that a subtle interplay of electron–electron and electron–ion interactions determines the magnitude of the on-site potential.
Issue Date: 6-Apr-2022
Date of Acceptance: 17-Mar-2022
URI: http://hdl.handle.net/10044/1/96255
DOI: 10.1088/2516-1075/ac5eaa
ISSN: 2516-1075
Publisher: IOP Publishing
Start Page: 1
End Page: 11
Journal / Book Title: Electronic Structure
Volume: 4
Issue: 2
Copyright Statement: © 2022 The Author(s). Published by IOP Publishing Ltd. Original content from this work may be used under the terms of the Creative Commons Attribution 4.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.
Sponsor/Funder: Engineering and Physical Sciences Research Council
Engineering & Physical Science Research Council (EPSRC)
Engineering and Physical Sciences Research Council
Funder's Grant Number: EP/L015579/1
EP/S025324/1
EPSRC (EP/L015579/1)
Keywords: cond-mat.mtrl-sci
cond-mat.mtrl-sci
cond-mat.str-el
Publication Status: Published
Open Access location: https://iopscience.iop.org/article/10.1088/2516-1075/ac5eaa
Online Publication Date: 2022-04-06
Appears in Collections:Materials
Faculty of Natural Sciences



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