A flat energy dispersion of electrons at the Fermi level of a material leads to instabilities in the electronic system and can drive phase transitions. Here we show that the flat band in graphene can be achieved by sandwiching a graphene monolayer by two cesium (Cs) layers. We investigate the flat band by a combination of angle-resolved photoemission spectroscopy experiment and the calculations. Our work highlights that charge transfer, zone folding of graphene bands, and the covalent bonding between C and Cs atoms are the origin of the flat energy band formation. Analysis of the Stoner criterion for the flat band suggests the presence of a ferromagnetic instability. The presented approach is an alternative route for obtaining flat band materials to twisting bilayer graphene which yields thermodynamically stable flat band materials in large areas.

Origin of the Flat Band in Heavily Cs-Doped Graphene / Ehlen, N.; Hell, M.; Marini, G.; Hasdeo, E. H.; Saito, R.; Falke, Y.; Goerbig, M. O.; Di Santo, G.; Petaccia, L.; Profeta, G.; Gruneis, A.. - In: ACS NANO. - ISSN 1936-0851. - 14:1(2020), pp. 1055-1069. [10.1021/acsnano.9b08622]

Origin of the Flat Band in Heavily Cs-Doped Graphene

Marini G.
Primo
;
2020-01-01

Abstract

A flat energy dispersion of electrons at the Fermi level of a material leads to instabilities in the electronic system and can drive phase transitions. Here we show that the flat band in graphene can be achieved by sandwiching a graphene monolayer by two cesium (Cs) layers. We investigate the flat band by a combination of angle-resolved photoemission spectroscopy experiment and the calculations. Our work highlights that charge transfer, zone folding of graphene bands, and the covalent bonding between C and Cs atoms are the origin of the flat energy band formation. Analysis of the Stoner criterion for the flat band suggests the presence of a ferromagnetic instability. The presented approach is an alternative route for obtaining flat band materials to twisting bilayer graphene which yields thermodynamically stable flat band materials in large areas.
2020
1
Ehlen, N.; Hell, M.; Marini, G.; Hasdeo, E. H.; Saito, R.; Falke, Y.; Goerbig, M. O.; Di Santo, G.; Petaccia, L.; Profeta, G.; Gruneis, A.
Origin of the Flat Band in Heavily Cs-Doped Graphene / Ehlen, N.; Hell, M.; Marini, G.; Hasdeo, E. H.; Saito, R.; Falke, Y.; Goerbig, M. O.; Di Santo, G.; Petaccia, L.; Profeta, G.; Gruneis, A.. - In: ACS NANO. - ISSN 1936-0851. - 14:1(2020), pp. 1055-1069. [10.1021/acsnano.9b08622]
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11572/397506
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