Density functional study of graphene antidot lattices: Roles of geometrical relaxation and spin

Fürst, Joachim Alexander; Pedersen, Thomas Garm; Brandbyge, Mads; Jauho, Antti–Pekka

doi:10.1103/physrevb.80.115117

Cited by 60 publications

(57 citation statements)

References 38 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…12 prove to be "magic". Notice that previously suggested antidot superlattices (Fürst et al, 2009;Pedersen et al, 2008) show comparable gaps, and are therefore equally valid candidates for turning graphene into a true semiconductor. The only difference is a subtle symmetry-related issue.…”

Section: Superlattices Of Vacancies or Holesmentioning

confidence: 98%

The Effect of Atomic-Scale Defects and Dopants on Graphene Electronic Structure

Martinazzo¹,

Casolo²,

Tantardini³

2011

Physics and Applications of Graphene - Theory

View full text Add to dashboard Cite

Graphene, being one-atom thick, is extremely sensitive to the presence of adsorbed atoms and molecules and, more generally, to defects such as vacancies, holes and/or substitutional dopants. This property, apart from being directly usable in molecular sensor devices, can also be employed to tune graphene electronic properties.Here we briefly review the basic features of atomic-scale defects that can be useful for material design. After a brief introduction on isolated p z defects, we analyse the electronic structure of multiple defective graphene substrates, and show how to predict the presence of microscopically ordered magnetic structures. Subsequently, we analyse the more complicated situation where the electronic structure, as modified by the presence of some defects, affects chemical reactivity of the substrate towards adsorption (chemisorption) of atomic/molecular species, leading to preferential sticking on specific lattice positions. Then, we consider the reverse problem, that is how to use defects to engineer graphene electronic properties. In this context, we show that arranging defects to form honeycomb-shaped superlattices (what we may call "supergraphenes") a sizeable gap opens in the band structure and new Dirac cones are created right close to the gapped region. Similarly, we show that substitutional dopants such as group IIIA/VA elements may have gapped quasiconical structures corresponding to massive Dirac carriers. All these possible structures might find important technological applications in the development of graphene-based logic transistors.

show abstract

Section: Superlattices Of Vacancies or Holesmentioning

confidence: 98%

The Effect of Atomic-Scale Defects and Dopants on Graphene Electronic Structure

Martinazzo¹,

Casolo²,

Tantardini³

2011

Physics and Applications of Graphene - Theory

View full text Add to dashboard Cite

show abstract

“…1,2 One possibility to overcome this hurdle is the use of graphene nanoribbons (GNRs), 3,4 or graphene antidot lattices (GALs). [5][6][7][8][9] The latter represent an interconnected array of GNRs within a graphene sheet and correspondingly allow for enhanced driving currents. Like their counterparts defined within semiconductor heterostructures, GALs are expected to exhibit a wide range of intricate transport properties, especially in magnetic fields where the competing length scales lead to rich physics.…”

Section: Introductionmentioning

confidence: 99%

Charge transport gap in graphene antidot lattices

et al. 2012

View full text Add to dashboard Cite

Graphene antidot lattices (GALs) offer an attractive approach to band-gap engineering in graphene. Theoretical studies indicate that the size of the opened gap is sensitive to the shape, size, and architecture of the nanoholes introduced into the graphene sheet. We have investigated the temperature-dependent electrical conductivity of GALs comprising 50-nm-diameter nanoholes with a pitch of 80, 100, and 200 nm, respectively. The data reveal the presence of localized states within a transport gap, whose interactions lead to a soft Coulomb gap and associated Efros-Shklovskii variable range hopping (ES-VRH). This conduction type is preserved upon application of magnetic fields up to 1 Tesla, above which a transition to Mott variable range hopping occurs. Such a crossover can alternatively be introduced at zero magnetic fields by increasing either the nanohole spacing or the gate-controlled carrier concentration. Furthermore, at intermediate magnetic fields, the hopping exponent assumes a value of 2/3, as predicted by percolation theory for ES-VRH under this condition.

show abstract

“…[18][19][20][21] The existence of intrinsic magnetism driven by atomicscale defects (such as vacancies, chemisorbed species, grain boundaries, etc.) has also been suggested theoretically, 20,[22][23][24][25][26][27][28][29][30] but remains fiercely debated on the experimental side. 31 It is indeed particularly difficult to achieve a precise experimental characterization of those defects, whereas the control of their density, positioning, or chemical reactivity seems an insurmountable challenge, jeopardizing a further use of magnetic properties in real devices.…”

Section: Introductionmentioning

confidence: 99%

Inducing and optimizing magnetism in graphene nanomeshes

et al. 2011

View full text Add to dashboard Cite

Using first-principles calculations, we explore the electronic and magnetic properties of graphene nanomesh (GNM), a regular network of large vacancies, produced either by lithography or nanoimprint. When removing an equal number of A and B sites of the graphene bipartite lattice, the nanomesh made mostly of zigzag (armchair) -type edges exhibit antiferromagnetic (spin unpolarized) states. In contrast, in situations of sublattice symmetry breaking, stable ferri(o)magnetic states are obtained. For hydrogen-passivated nanomesh, the formation energy is dramatically decreased, and ground state is found to strongly depend on the vacancies shape and size. For triangular-shaped holes, the obtained net magnetic moments increase with the number difference of removed A and B sites in agreement with Lieb's theorem for even A + B. For odd A + B triangular meshes and all cases of nontriangular nanomeshes, including the one with even A + B, Lieb's theorem does not hold anymore, which can be partially attributed to the introduction of armchair edges. In addition, large triangular-shaped GNMs could be as robust as nontriangular GNMs, providing a possible solution to overcome one of the crucial challenges for the sp magnetism. Finally, significant exchange-splitting values as large as ∼ 0.5 eV can be obtained for highly asymmetric structures evidencing the potential of GNM for room-temperature carbon-based spintronics. These results demonstrate that a turn from zero-dimensional graphene nanoflakes throughout one-dimensional graphene nanoribbons with zigzag edges to GNM breaks localization of unpaired electrons and provides deviation from the rules based on Lieb's theorem. Such delocalization of the electrons leads the switch of the ground state of a system from an antiferromagnetic narrow gap insulator discussed for graphene nanoribons to a ferromagnetic or nonmagnetic metal.

show abstract

Density functional study of graphene antidot lattices: Roles of geometrical relaxation and spin

Cited by 60 publications

References 38 publications

The Effect of Atomic-Scale Defects and Dopants on Graphene Electronic Structure

The Effect of Atomic-Scale Defects and Dopants on Graphene Electronic Structure

Charge transport gap in graphene antidot lattices

Inducing and optimizing magnetism in graphene nanomeshes

Contact Info

Product

Resources

About