TY - JOUR

T1 - Spin-Orbit Coupling Induced Gap in Graphene on Pt(111) with Intercalated Pb Monolayer

AU - Klimovskikh, Ilya I.

AU - Otrokov, Mikhail M.

AU - Voroshnin, Vladimir Yu

AU - Sostina, Daria

AU - Petaccia, Luca

AU - Di Santo, Giovanni

AU - Thakur, Sangeeta

AU - Chulkov, Evgueni V.

AU - Shikin, Alexander M.

N1 - Publisher Copyright: © 2016 American Chemical Society. Copyright: Copyright 2017 Elsevier B.V., All rights reserved.

PY - 2017/1/24

Y1 - 2017/1/24

N2 - 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.

AB - 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.

KW - ARPES

KW - electronic structure

KW - graphene

KW - spin-orbit coupling

KW - topological insulator

UR - http://www.scopus.com/inward/record.url?scp=85018193190&partnerID=8YFLogxK

U2 - 10.1021/acsnano.6b05982

DO - 10.1021/acsnano.6b05982

M3 - Article

C2 - 28005333

VL - 11

SP - 368

EP - 374

JO - ACS Nano

JF - ACS Nano

SN - 1936-0851

IS - 1

ER -