The stacking order of multilayer graphene has a profound influence on its electronic properties. In particular, it has been predicted that a rhombohedral stacking sequence displays a very flat conducting surface state: the longer the sequence, the flatter the band. In such a flat band, the role of electron electron correlation is enhanced, possibly resulting in high T-c superconductivity, magnetic order, or charge density wave order. Here we demonstrate that rhombohedral multilayers are easily obtained by epitaxial growth on 3C-S1C(111) on a 2 degrees off-axis 6H-SiC(0001). The resulting samples contain rhombohedral sequences of five layers on 70% of the surface. We confirm the presence of the flat band at the Fermi level by scanning tunneling spectroscopy and angle-resolved photoemission spectroscopy, in close agreement with the predictions of density functional theory calculations.
Evidence for Flat Bands near the Fermi Level in Epitaxial Rhombohedral Multilayer Graphene / Pierucci, D., Sediri, H., Hajlaoui, M., Girard, J.C., Brumme, T., Calandra, M., Velez Fort, E., Patriarche, G., Silly, M.G., Ferro, G., Souliere, V., Marangolo, M., Sirotti, F., Mauri, F., Ouerghi, A.. - In: ACS NANO. - ISSN 1936-0851. - 9:5(2015), pp. 5432-5439. [10.1021/acsnano.5b01239]
Evidence for Flat Bands near the Fermi Level in Epitaxial Rhombohedral Multilayer Graphene
MAURI, FRANCESCO;
2015
Abstract
The stacking order of multilayer graphene has a profound influence on its electronic properties. In particular, it has been predicted that a rhombohedral stacking sequence displays a very flat conducting surface state: the longer the sequence, the flatter the band. In such a flat band, the role of electron electron correlation is enhanced, possibly resulting in high T-c superconductivity, magnetic order, or charge density wave order. Here we demonstrate that rhombohedral multilayers are easily obtained by epitaxial growth on 3C-S1C(111) on a 2 degrees off-axis 6H-SiC(0001). The resulting samples contain rhombohedral sequences of five layers on 70% of the surface. We confirm the presence of the flat band at the Fermi level by scanning tunneling spectroscopy and angle-resolved photoemission spectroscopy, in close agreement with the predictions of density functional theory calculations.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
