Fractal energy gaps and topological invariants in hBN/graphene/hBN double moiré systems

Autor:	Hiroki Oka, Mikito Koshino
Rok vydání:	2021
Předmět:	Physics Condensed Matter - Mesoscale and Nanoscale Physics Condensed matter physics biology Graphene Position and momentum space Electronic structure biology.organism_classification Projection (linear algebra) law.invention Plain wave Fractal law Quasiperiodic function Polygon
Zdroj:	Physical Review B. 104
ISSN:	2469-9969 2469-9950
DOI:	10.1103/physrevb.104.035306
Popis:	We calculate the electronic structure in quasiperiodic double-moir\'e systems of graphene sandwiched by hexagonal boron nitride, and identify the topological invariants of energy gaps. We find that the electronic spectrum contains a number of minigaps, and they exhibit a recursive fractal structure similar to the Hofstadter butterfly when plotted against the twist angle. Each of the energy gaps can be characterized by a set of integers, which are associated with an area in the momentum space. The corresponding area is geometrically interpreted as a quasi Brillouin zone, which is a polygon enclosed by multiple Bragg planes of the composite periods and can be uniquely specified by the plain wave projection in the weak potential limit. Comment: 17 pages, 11 figures
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_dedup___::f00ad0284e1201b871dcadf5853e508b https://doi.org/10.1103/physrevb.104.035306 Zobrazit plný text záznamu