Universität zu Köln

Attig, Jan, Park, Jinhong ORCID: 0000-0001-6710-1031, Scherer, Michael M., Trebst, Simon, Altland, Alexander and Rosch, Achim ORCID: 0000-0002-6586-5721 (2021). Universal principles of moire band structures. 2D Mater., 8 (4). BRISTOL: IOP PUBLISHING LTD. ISSN 2053-1583

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Abstract

Moire materials provide a highly tunable environment for the realization of band structures with engineered physical properties. Specifically, moire structures with Fermi surface flat bands-a synthetic environment for the realization of correlated phases-have moire unit cells containing thousands of atoms and tantalizingly complex band structures. In this paper we show that statistical principles go a long way in explaining universal physical properties of these systems. Our approach builds on three conceptual elements: the presence of quantum chaos caused by the effective irregularity of the atomic configurations on short length scales, Anderson localization in momentum space, and the presence of approximate crystalline symmetries. Which of these principles dominates depends on material parameters such as the extension of the Fermi surface or the strength of the moire lattice potential. The phenomenological consequences of this competition are predictions for the characteristic group velocity of moire bands, a primary indicator for their average flatness. In addition to these generic features, we identify structures outside the statistical context, notably almost flat bands close to the extrema of the unperturbed spectra, and the celebrated zero energy 'magic angle' flat bands, where the latter require exceptionally fine tuned material parameters.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Attig, Jan UNSPECIFIED UNSPECIFIED UNSPECIFIED Park, Jinhong UNSPECIFIED orcid.org/0000-0001-6710-1031 UNSPECIFIED Scherer, Michael M. UNSPECIFIED UNSPECIFIED UNSPECIFIED Trebst, Simon UNSPECIFIED UNSPECIFIED UNSPECIFIED Altland, Alexander UNSPECIFIED UNSPECIFIED UNSPECIFIED Rosch, Achim UNSPECIFIED orcid.org/0000-0002-6586-5721 UNSPECIFIED
URN:	urn:nbn:de:hbz:38-566865
DOI:	10.1088/2053-1583/ac1cf0
Journal or Publication Title:	2D Mater.
Volume:	8
Number:	4
Date:	2021
Publisher:	IOP PUBLISHING LTD
Place of Publication:	BRISTOL
ISSN:	2053-1583
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language MAGIC-ANGLE; CORRELATED STATES; GRAPHENE; INSULATOR; PHYSICS; MOTT Multiple languages Materials Science, Multidisciplinary Multiple languages
URI:	http://kups.ub.uni-koeln.de/id/eprint/56686