Extremely flat band in bilayer graphene.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 30430134.
- Also identified by DOI 10.1126/sciadv.aau0059 and PMC identifier 6226281.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
We propose a novel mechanism of flat band formation based on the relative biasing of only one sublattice against other sublattices in a honeycomb lattice bilayer. The mechanism allows modification of the band dispersion from parabolic to "Mexican hat"-like through the formation of a flattened band. The mechanism is well applicable for bilayer graphene-both doped and undoped. By angle-resolved photoemission from bilayer graphene on SiC, we demonstrate the possibility of realizing this extremely flattened band (< 2-meV dispersion), which extends two-dimensionally in a k-space area around the <math xmlns="http://www.w3.org/1998/Math/MathML"> <mrow> <mrow><mover><mi>K</mi> <mo>¯</mo></mover> </mrow> </mrow> </math> point and results in a disk-like constant energy cut. We argue that our two-dimensional flat band model and the experimental results have the potential to contribute to achieving superconductivity of graphene- or graphite-based systems at elevated temperatures.