In-plane orientation effects on the electronic structure, stability, and Raman scattering of monolayer graphene on Ir(111)

Starodub, Elena; Bostwick, Aaron; Moreschini, Luca; Nie, Shu; Gabaly, Farid El; McCarty, K. F.; Rotenberg, Eli

doi:10.1103/physrevb.83.125428

Cited by 154 publications

(218 citation statements)

References 60 publications

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“…The characteristic π bands and σ bands of graphene are observed clearly. Different from graphene grown on other metal substrates 21,22 , our data show negligible contribution from the Pt(111) substrate bands or Moiré superlattice bands, which makes it more convenient to probe the electronic structure of graphene. Peaks from π band along the Γ-M direction of the R0°domain are also observed at higher binding energy.…”

Section: Resultsmentioning

confidence: 93%

Monolayer charge-neutral graphene on platinum with extremely weak electron-phonon coupling

et al. 2015

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Epitaxial growth of graphene on transition metal substrates is an important route for obtaining large scale graphene. However, the interaction between graphene and the substrate often leads to multiple orientations, distorted graphene band structure, large doping and strong electron-phonon coupling. Here we report the growth of monolayer graphene with high crystalline quality on Pt(111) substrate by using very low concentration of internal carbon source with high annealing temperature. The controlled growth leads to electronically decoupled graphene: it is nearly charge neutral and has extremely weak electron-phonon coupling (coupling strength λ ≈ 0.056) as revealed by angle-resolved photoemission spectroscopic measurements. The thermodynamics and kinetics of carbon diffusion process is investigated by DFT calculation. Such graphene with negligible graphene-substrate interaction provides an important platform for fundamental research as well as device applications when combined with nondestructive sample transfer technique.

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Section: Resultsmentioning

confidence: 93%

Monolayer charge-neutral graphene on platinum with extremely weak electron-phonon coupling

et al. 2015

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“…Graphene on Ir(111) is a well-studied system with a weak interaction with the substrate [22][23][24][25][26]. It is characterized by the 9.3 × 9.3 moiré superstructure, and geometrical corrugation which arises from the lattice mismatch of graphene with respect to the Ir(111).…”

Section: Introductionmentioning

confidence: 99%

Variation of the character of spin-orbit interaction by Pt intercalation underneath graphene on Ir(111)

et al. 2015

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The modification of the graphene spin structure is of interest for novel possibilities of application of graphene in spintronics. The most exciting of them demand not only high value of spin-orbit splitting of the graphene states, but non-Rashba behavior of the splitting and spatial modulation of the spin-orbit interaction. In this work we study the spin and electronic structure of graphene on Ir(111) with intercalated Pt monolayer. Pt interlayer does not change the 9.3 × 9.3 superlattice of graphene, while the spin structure of the Dirac cone becomes modified. It is shown that the Rashba splitting of the π state is reduced, while hybridization of the graphene and substrate states leads to a spin-dependent avoided-crossing effect near the Fermi level. Such a variation of spin-orbit interaction combined with the superlattice effects can induce a topological phase in graphene.

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“…Here, we define the relative work function as the energy for which electron reflectivity drops by 10% from total reflectance [26]. Following previous works [7,13] to track Co intercalation, we take advantage of the fact that the WF of graphene-terminated metal surfaces is often lower than the WF of the corresponding clean metal surfaces [27].…”

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confidence: 99%

“…Following previous works [7,13] to track Co intercalation, we take advantage of the fact that the WF of graphene-terminated metal surfaces is often lower than the WF of the corresponding clean metal surfaces [27]. This is particularly true for Co and Ir: δWF Co =WF Co -WF Gr/Co ∼1.7 eV [27] and δWF Ir =WF Ir -WF Gr/Ir ∼1 eV [23,26].…”

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confidence: 99%

Cobalt intercalation at the graphene/iridium(111) interface: Influence of rotational domains, wrinkles, and atomic steps

Vlaic

Kimouche

Coraux

et al. 2014

Applied Physics Letters

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Using low-energy electron microscopy, we study Co intercalation under graphene grown on Ir(111). Depending on the rotational domain of graphene on which it is deposited, Co is found intercalated at different locations. While intercalated Co is observed preferentially at the substrate step edges below certain rotational domains, it is mostly found close to wrinkles below other domains. These results indicate that curved regions (near substrate atomic steps and wrinkles) of the graphene sheet facilitate Co intercalation and suggest that the strength of the graphene/Ir interaction determines which pathway is energetically more favorable.In view of potential technological appications, the ability to modify and control the properties of a graphene layer has been a central issue since its discovery [1]. The intercalation of foreign atoms or molecules between a graphene sheet and its substrate often affects the electronic and magnetic properties of the considered interface. For example, the intercalation of noble metals [2,3] or hydrogen atoms [4] can be used to reduce the interaction between graphene and its substrate, and even restore the electronic properties of free-standing graphene, while the intercalation of alkali metals is an efficient mean to control the doping level of graphene [5]. Intercalation of a ferromagnetic transition metal can also enhance the net magnetic moment induced in carbon atoms when graphene is in contact with a magnetic surface [6], and is a promising route to fabricate graphene/ferromagnetic metal hybrid structures with perpendicular magnetic anisotropy [7,8].Understanding where and how a foreign species intercalates below graphene is a challenging task, and different scenarios have been proposed. While oxygen intercalates at the free edges of graphene grown on Ru(0001) [9, 10] and on Ir(111) [11], alkali metals instead may intercalate at the substrate step edges or at boundaries between different rotational domains in graphene/Ni(111) [5] and in graphite [12]. Regarding transition metals, the intercalation mechanism remains elusive. While it has been demonstrated that pre-existing defects in graphene, such as vacancies or pentagon-heptagon pairs, reduce the required energy to trigger intercalation [13,14], several recent experimental works have shown that other mechanisms could be at work. In particular, the formation of atomic defects, not pre-existing in the graphene layer but induced by the contact with a transition metal cluster, with subsequent restoring of the carbon-carbon bonds, has been suggested as a possible way for metal intercalation [14][15][16]. In this work, low-energy electron microscopy [17,18] (LEEM) is used to study cobalt intercalation at moderate annealing temperature (about 125 • C) underneath graphene grown on an iridium (111) surface. Depending on the rotational orientation of the graphene domain, we find Co intercalated at differ-

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In-plane orientation effects on the electronic structure, stability, and Raman scattering of monolayer graphene on Ir(111)

Cited by 154 publications

References 60 publications

Monolayer charge-neutral graphene on platinum with extremely weak electron-phonon coupling

Monolayer charge-neutral graphene on platinum with extremely weak electron-phonon coupling

Variation of the character of spin-orbit interaction by Pt intercalation underneath graphene on Ir(111)

Cobalt intercalation at the graphene/iridium(111) interface: Influence of rotational domains, wrinkles, and atomic steps

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