Unconventional Flat Chern Bands and 2e Charges in Skyrmionic Moire Superlattices
Metadata only
Datum
2023-05-24Typ
- Journal Article
ETH Bibliographie
yes
Altmetrics
Abstract
The interplay of topological characteristics in real space and reciprocal space can lead to the emergence of unconventional topological phases. In this Letter, we implement a novel mechanism for generating higher-Chern flat bands on the basis of twisted bilayer graphene (TBG) coupled to topological magnetic structures in the form of the skyrmion lattice. In particular, we discover a scenario for generating vertical bar C vertical bar = 2 dispersionless electronic bands when the skyrmion periodicity and the moire ' periodicity match. Following the Wilczek argument, the statistics of the charge-carrying excitations in this case is bosonic, characterized by electronic charge Q = 2e, which is even in units of electron charge e. The skyrmion coupling strength triggering the topological phase transition is realistic, with its lower bound estimated as 4 meV. The Hofstadter butterfly spectrum results in an unexpected quantum Hall conductance sequence +/- 2e(2)/h, +/- 4e(2)/h, ... for TBG with the skyrmion order. Mehr anzeigen
Publikationsstatus
publishedExterne Links
Zeitschrift / Serie
Nano LettersBand
Seiten / Artikelnummer
Verlag
American Chemical SocietyThema
twisted bilayer graphene; moire lattice relaxation; skyrmions; flat electronic bands; hybrid Wannier functions; quantum Hall effectETH Bibliographie
yes
Altmetrics