Perfect and Controllable Nesting in Minimally Twisted Bilayer Graphene

Fleischmann M, Gupta R, Wullschläger F, Theil S, Weckbecker D, Meded V, Sharma S, Meyer B, Shallcross S (2020)

Publication Type: Journal article

Publication year: 2020

Journal

Nano Letters American Chemical Society

DOI: 10.1021/acs.nanolett.9b04027

Abstract

Parallel ("nested") regions of a Fermi surface (FS) drive instabilities of the electron fluid, for example, the spin density wave in elemental chromium. In one-dimensional materials, the FS is trivially fully nested (a single nesting vector connects two "Fermi dots"), while in higher dimensions only a fraction of the FS consists of parallel sheets. We demonstrate that the tiny angle regime of twist bilayer graphene (TBLG) possesses a phase, accessible by interlayer bias, in which the FS consists entirely of nestable "Fermi lines", the first example of a completely nested FS in a two-dimensional (2D) material. This nested phase is found both in the ideal as well as relaxed structure of the twist bilayer. We demonstrate excellent agreement with recent STM images of topological states in this material and elucidate the connection between these and the underlying Fermiology. We show that the geometry of the Fermi lines network is controllable by the strength of the applied interlayer bias, and thus TBLG offers unprecedented access to the physics of FS nesting in 2D materials.

Authors with CRIS profile

Maximilian Fleischmann Lehrstuhl für Theoretische Festkörperphysik Reena Gupta Sonderforschungsbereich 953/3 Synthetische Kohlenstoffallotrope Florian Wullschläger Interdisziplinäres Zentrum für Molekulare Materialien (ICMM) Dominik Weckbecker Lehrstuhl für Theoretische Festkörperphysik Bernd Meyer Professur für Computational Chemistry Sam Shallcross Lehrstuhl für Theoretische Festkörperphysik

Involved external institutions

Max-Born-Institut für Nichtlineare Optik und Kurzzeitspektroskopie im Forschungsverbund Berlin e.V. / Max Born Institute for Nonlinear Optics and Short Pulse Spectroscopy DE Germany (DE) Karlsruhe Institute of Technology (KIT) DE Germany (DE)

How to cite

APA:

Fleischmann, M., Gupta, R., Wullschläger, F., Theil, S., Weckbecker, D., Meded, V.,... Shallcross, S. (2020). Perfect and Controllable Nesting in Minimally Twisted Bilayer Graphene. Nano Letters. https://doi.org/10.1021/acs.nanolett.9b04027

MLA:

Fleischmann, Maximilian, et al. "Perfect and Controllable Nesting in Minimally Twisted Bilayer Graphene." Nano Letters (2020).

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