title: Spin-Orbit Coupling Induced Gap in Graphene on Pt(111) with Intercalated Pb Monolayer.
abstract: Graphene is one of the most promising materials for nanoelectronics owing to its unique Dirac cone-like dispersion of the electronic state and high mobility of the charge carriers. However, to facilitate the implementation of the graphene-based devices, an essential change of its electronic structure, a creation of the band gap should controllably be done. Brought about by two fundamentally different mechanisms, a sublattice symmetry breaking or an induced strong spin-orbit interaction, the band gap appearance can drive graphene into a narrow-gap semiconductor or a 2D topological insulator phase, respectively, with both cases being technologically relevant. The later case, characterized by a spin-orbit gap between the valence and conduction bands, can give rise to the spin-polarized topologically protected edge states. Here, we study the effect of the spin-orbit interaction enhancement in graphene placed in contact with a lead monolayer. By means of angle-resolved photoemission spectroscopy, we show that intercalation of the Pb interlayer between the graphene sheet and the Pt(111) surface leads to formation of a gap of ∼200 meV at the Dirac point of graphene. Spin-resolved measurements confirm the splitting to be of a spin-orbit nature, and the measured near-gap spin structure resembles that of the quantum spin Hall state in graphene, proposed by Kane and Mele [ Phys. Rev. Lett. 2005 , 95 , 226801 ]. With a bandstructure tuned in this way, graphene acquires a functionality going beyond its intrinsic properties and becomes more attractive for possible spintronic applications.
authors.affiliation: Saint Petersburg State University , 198504 Saint Petersburg, Russia.
authors.forename: Ilya I
authors.identifier: 0000-0003-0243-0322
authors.initials: II
authors.lastname: Klimovskikh
authors.affiliation: Saint Petersburg State University , 198504 Saint Petersburg, Russia.|Donostia International Physics Center (DIPC) , 20018 San Sebastián/Donostia, Basque Country, Spain.
authors.forename: Mikhail M
authors.initials: MM
authors.lastname: Otrokov
authors.affiliation: Saint Petersburg State University , 198504 Saint Petersburg, Russia.
authors.forename: Vladimir Yu
authors.initials: VY
authors.lastname: Voroshnin
authors.affiliation: Saint Petersburg State University , 198504 Saint Petersburg, Russia.
authors.forename: Daria
authors.initials: D
authors.lastname: Sostina
authors.affiliation: Elettra Sincrotrone Trieste , Strada Statale 14 km 163.5, 34149 Trieste, Italy.
authors.forename: Luca
authors.initials: L
authors.lastname: Petaccia
authors.affiliation: Elettra Sincrotrone Trieste , Strada Statale 14 km 163.5, 34149 Trieste, Italy.
authors.forename: Giovanni
authors.initials: G
authors.lastname: Di Santo
authors.affiliation: Elettra Sincrotrone Trieste , Strada Statale 14 km 163.5, 34149 Trieste, Italy.
authors.forename: Sangeeta
authors.initials: S
authors.lastname: Thakur
authors.affiliation: Saint Petersburg State University , 198504 Saint Petersburg, Russia.|Tomsk State University , 634050 Tomsk, Russian Federation.|Donostia International Physics Center (DIPC) , 20018 San Sebastián/Donostia, Basque Country, Spain.|Departamento de Fı́sica de Materiales UPV/EHU, Centro de Fı́sica de Materiales CFM - MPC and Centro Mixto CSIC-UPV/EHU , 20080 San Sebastián/Donostia, Basque Country, Spain.
authors.forename: Evgueni V
authors.initials: EV
authors.lastname: Chulkov
authors.affiliation: Saint Petersburg State University , 198504 Saint Petersburg, Russia.
authors.forename: Alexander M
authors.initials: AM
authors.lastname: Shikin
keywords: ARPES; electronic structure; graphene; spin−orbit coupling; topological insulator