1 research outputs found
Flat Electronic Bands in Long Sequences of Rhombohedral-stacked Multilayer Graphene
The crystallographic stacking order in multilayer graphene plays an important
role in determining its electronic properties. It has been predicted that a
rhombohedral (ABC) stacking displays a conducting surface state with flat
electronic dispersion. In such a flat band, the role of electron-electron
correlation is enhanced possibly resulting in high Tc superconductivity, charge
density wave or magnetic orders. Clean experimental band structure measurements
of ABC stacked specimens are missing because the samples are usually too small
in size. Here, we directly image the band structure of large multilayer
graphene flake containing approximately 14 consecutive ABC layers.
Angle-resolved photoemission spectroscopy experiments reveal the flat
electronic bands near the K point extends by 0.13 {\AA}-1 at the Fermi level at
liquid nitrogen temperature. First-principle calculations identify the
electronic ground state as an antiferromagnetic state with a band gap of about
40 meV