Tuning the magnetic moments in zigzag graphene nanoribbons: Effects of metal substrates

Chen, Jingzhe; Vanin, Marco; Guo, Hong

doi:10.1103/physrevb.86.075146

Cited by 21 publications

(16 citation statements)

References 29 publications

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“…4,14 For the ZGNRs on metal substrates (such as Au, Pt, Ni, Cu, Al, Ag, Pd), MMs in ZGNR on s-dominated metal surfaces can be reordered using E ext 22 because of the prevalence of electrostatic interaction between ZGNR and s-dominated surfaces. For ZGNRs on p-and d-dominated metal surfaces, tuning with E ext is less efficient 22 because of strong interaction between carbon π -orbitals and metal substrate during chemical adsorption. Based on ab initio density functional theory (DFT) calculations, 15 application of E ext across the width of ZGNRs effectively cancels energy degeneracy of two edges, resulting in spin-selective ZGNRs.…”

Section: Introductionmentioning

confidence: 99%

Tuning the band structure, magnetic and transport properties of the zigzag graphene nanoribbons/hexagonal boron nitride heterostructures by transverse electric field

Ilyasov

Meshi

Nguyen

et al. 2014

The Journal of Chemical Physics

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The paper presents the results of ab initio study of the opportunities for tuning the band structure, magnetic and transport properties of zigzag graphene nanoribbon (8-ZGNR) on hexagonal boron nitride (h-BN(0001)) semiconductor heterostructure by transverse electric field (E(ext)). This study was performed within the framework of the density functional theory (DFT) using Grimme's (DFT-D2) scheme. We established the critical values of E(ext) for the 8-ZGNR/h-BN(0001) heterostructure, thereby providing for semiconductor-halfmetal transition in one of electron spin configurations. This study also showed that the degeneration in energy of the localized edge states is removed when E(ext) is applied. In ZGNR/h-BN (0001) heterostructure, value of the splitting energy was higher than one in ZGNRs without substrate. We determined the effect of low E(ext) applied to the 8-ZGNR/h-BN (0001) semiconductor heterostructure on the preserved local magnetic moment (LMM) (0.3μ(B)) of edge carbon atoms. The transport properties of the 8-ZGNR/h-BN(0001) semiconductor heterostructure can be controlled using E(ext). In particular, at a critical value of the positive potential, the electron mobility can increase to 7× 10(5) cm(2)/V s or remain at zero in the spin-up and spin-down electron subsystems, respectively. We established that magnetic moments (MMs), band gaps, and carrier mobility can be altered using E(ext). These abilities enable the use of 8-ZGNR/h-BN(0001) semiconductor heterostructure in spintronics.

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Section: Introductionmentioning

confidence: 99%

Tuning the band structure, magnetic and transport properties of the zigzag graphene nanoribbons/hexagonal boron nitride heterostructures by transverse electric field

Ilyasov

Meshi

Nguyen

et al. 2014

The Journal of Chemical Physics

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“…Recently, many theoretical interests have been attracted to the study of substrate influence on the electronic structure, thermal conductivity and growth mechanisms in bulk graphene [4,5] and graphene nanoribbons [6,7]. Experimentally, the effect of semi-insulating and metal substrates has been investigated by using ultraviolet and far-infrared photoelectron spectroscopy [8,9].…”

mentioning

confidence: 99%

“…Wj, 73.22.Pr,Graphene, an artificial material discovered recently [1], is a promising candidate in future microelectronic devices due to its extraordinary electronic [2] and optical properties [3]. Recently, many theoretical interests have been attracted to the study of substrate influence on the electronic structure, thermal conductivity and growth mechanisms in bulk graphene [4,5] and graphene nanoribbons [6,7]. Experimentally, the effect of semi-insulating and metal substrates has been investigated by using ultraviolet and far-infrared photoelectron spectroscopy [8,9].…”

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confidence: 99%

Substrate effects on quasiparticles and excitons in graphene nanoflakes

Sheng

Sun

Zhou

et al. 2013

Applied Physics Letters

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The effects of substrate on electronic and optical properties of triangular and hexagonal graphene nanoflakes with armchair edges are investigated by using a configuration interaction approach beyond double excitation scheme. The quasiparticle correction to the energy gap and exciton binding energy are found to be dominated by the long-range Coulomb interactions and exhibit similar dependence on the dielectric constant of the substrate, which leads to a cancellation of their contributions to the optical gap. As a result, the optical gaps are shown to be insensitive to the dielectric environment and unexpectedly close to the single-particle gaps. PACS numbers: 78.67. Wj, 73.22.Pr,Graphene, an artificial material discovered recently [1], is a promising candidate in future microelectronic devices due to its extraordinary electronic [2] and optical properties [3]. Recently, many theoretical interests have been attracted to the study of substrate influence on the electronic structure, thermal conductivity and growth mechanisms in bulk graphene [4,5] and graphene nanoribbons [6,7]. Experimentally, the effect of semi-insulating and metal substrates has been investigated by using ultraviolet and far-infrared photoelectron spectroscopy [8,9].Although bulk graphene has almost zero band-gap, a finite gap can be opened and even engineered by quantum confinement effect in graphene nanoribbons and nanoflakes [10]. Electron-electron interactions would further modify this quasiparticle gap into the optical gap, which is commonly known as the excitonic effect [11][12][13][14]. Many-body perturbation theory and configuration interaction method have been applied to calculate exciton binding energies in quasi-one-dimensional graphene nanoribbons [15,16], and excitonic absorption in triangular graphene quantum dots with zigzag edges [17,18]. Undoubtedly, the study of quasiparticle and excitonic effects in these structures requires a proper treatment of the dielectric screening effect [19] At present, however, there have been very few attempts to investigate substrate effects on electronic structure and optical properties in graphene nanoflakes. In this letter, we will explore how various substrates affects quasiparticle self-energies, exciton binding energies and optical gaps in graphene nanoflakes. An interesting question that how sensitive the optical transitions are to the dielectric environment in nanographene structures, which is believed to have both fundamental and practical importance, will be answered.We consider two types of armchair graphene nanoflakes placed on various substrates such as SiO 2 , diamond, and SiC. Figure 1 gives a schematic view of our first model system, a triangular graphene nanoflake. The number of carbon rings along each edge is set to be N = 4, which corresponds to a total number of atoms n = 60. The single-particle states are obtained by the use of the tight-binding model with the nearest-neighbor hopping. The matrix element of the single-particle Hamiltonian for electron p is given by i|Ĥ(p)|j = t...

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“…The fact prevents graphene from being used in semiconductor devices. Known solutions to the problem employ various (dielectric 5,6 and metal-based 7 ) substrates, graphene nanoribbons 8,9 and electric field. 10 Graphene nanoribbons have a peculiarity demonstrating non-linear dispersion relation for the low-energy spectrum of π -electrons.…”

Section: Introductionmentioning

confidence: 99%

“…Therefore, for ZGNR/substrate systems influence of two factors should be expected: edge and substrate effects. Until now the majority of theoretical band structure research works, except for a few, 8 have been performed for freestanding ZGNR using the tight binding method. For substrate-based graphene growth, chemical deposition or chemical epitaxy are employed as very promising methods.…”

Section: Introductionmentioning

confidence: 99%

Edge and substrate-induced bandgap in zigzag graphene nanoribbons on the hexagonal nitride boron 8-ZGNR/h-BN(0001)

et al. 2013

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The results of DFT (GGA-PBEsol) and DFT(PBE)-D2 study of the band structure of zigzag graphene nanoribbons on hexagonal nitride boron 8-ZGNR/h-BN(0001) are presented, suitable as potential base for new materials for spintronics. It offers a study of regularities in the changes of the valence band electron structure and the induction of the energy gap in the series 8-ZGNR → 8-ZGNR/h-BN(0001) → graphene/h-BN(0001). The peculiarities of the spin state at the Fermi level, the roles of the edge effect and the effect of substrate in formation of the band gap in 8-ZGNR/h-BN(0001) system are discussed. Our calculations shown that vdW-correction plays an important role in the adsorption of GNR on h-BN and results in reduction of the interplanar distances in equilibrium systems ZGNRs/h-BN(0001). As a result of the structural changes we have obtained new values of the energy gap in the 8-ZGNR-AF and 8-ZGNR-AF/h-BN(0001) systems. The paper demonstrates appearance of 600 meV energy gap in the 8-ZGNR/h-BN(0001) interface. The contributions of nanoribbon edges and the substrate in formation of the gap have been differentiated for the first time. The estimations of local magnetic moments on carbon atoms are made. Shown that in case of ferromagnetic ordering substrate presense causes insignificant splitting of the bands. The splitting reached only (14-28 meV). Since the electronic states of a suspended GNR in point (k=π) are degenerate near the Fermi level, we can assume that the above splitting in 8-ZGNR/h-BN(0001) is only determined by the contribution of the h-BN(0001) substrate.

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Tuning the magnetic moments in zigzag graphene nanoribbons: Effects of metal substrates

Cited by 21 publications

References 29 publications

Tuning the band structure, magnetic and transport properties of the zigzag graphene nanoribbons/hexagonal boron nitride heterostructures by transverse electric field

Tuning the band structure, magnetic and transport properties of the zigzag graphene nanoribbons/hexagonal boron nitride heterostructures by transverse electric field

Substrate effects on quasiparticles and excitons in graphene nanoflakes

Edge and substrate-induced bandgap in zigzag graphene nanoribbons on the hexagonal nitride boron 8-ZGNR/h-BN(0001)

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