Orbital magnetism of graphene flakes

Ominato, Yuya; Koshino, Mikito

doi:10.1103/physrevb.87.115433

Cited by 54 publications

(50 citation statements)

References 71 publications

(133 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This behavior is also confirmed in Ref. [47], where the orbital magnetic properties of hexagonal and triangular graphene nanostructures are numerically studied within tight-binding approximation.…”

Section: B Comparability Of Numerical Results With Analytical Bulk Dsupporting

confidence: 68%

Orbital magnetism of graphene nanostructures: Bulk and confinement effects

Heße

Richter

2014

Phys. Rev. B

View full text Add to dashboard Cite

We consider the orbital magnetic properties of noninteracting charge carriers in graphene-based nanostructures in the low-energy regime. The magnetic response of such systems results both from bulk contributions and from confinement effects that can be particularly strong in ballistic quantum dots. First we provide a comprehensive study of the magnetic susceptibility χ of bulk graphene in a magnetic field for the different regimes arising from the relative magnitudes of the energy scales involved, i.e., temperature, Landau-level spacing, and chemical potential. We show that for finite temperature or chemical potential, χ is not divergent although the diamagnetic contribution χ 0 from the filled valance band exhibits the well-known −B −1/2 dependence. We further derive oscillatory modulations of χ , corresponding to de Haas-van Alphen oscillations of conventional two-dimensional electron gases. These oscillations can be large in graphene, thereby compensating the diamagnetic contribution χ 0 and yielding a net paramagnetic susceptibility for certain energy and magnetic field regimes. Second, we predict and analyze corresponding strong, confinement-induced susceptibility oscillations in graphene-based quantum dots with amplitudes distinctly exceeding the corresponding bulk susceptibility. Within a semiclassical approach we derive generic expressions for orbital magnetism of graphene quantum dots with regular classical dynamics. Graphene-specific features can be traced back to pseudospin interference along the underlying periodic orbits. We demonstrate the quality of the semiclassical approximation by comparison with quantum-mechanical results for two exemplary mesoscopic systems, a graphene disk with infinite mass-type edges, and a rectangular graphene structure with armchair and zigzag edges, using numerical tight-binding calculations in the latter case.

show abstract

Section: B Comparability Of Numerical Results With Analytical Bulk Dsupporting

confidence: 68%

Orbital magnetism of graphene nanostructures: Bulk and confinement effects

Heße

Richter

2014

Phys. Rev. B

View full text Add to dashboard Cite

show abstract

“…The localized edge states are not gathered exactly at E = 0, but are mostly distributed nearby, inside the band, corresponded to the gap for triangular clusters. In strike contrast to the triangular case, these dispersed states give the considerable contribution to the orbital diamagnetism 26,29 , demonstrating the broad diamagnetic peak at E ∼ 0 in the orbital diamagnetic susceptibility (Fig.4b). In general, the diamagnetic response is larger in hexagonal GQDs as compare to triangular GQDs.…”

Section: Hexmentioning

confidence: 91%

“…Before consider multi-layer clusters we describe the principal electronic and magnetic properties of singlelayer clusters with zig-zag edges, studied in [16][17][18][19][20][21][22][23][24][25][26][27][28][29] .…”

Section: Graphene Quantum Dotsmentioning

confidence: 99%

“…Alongside, flake-like graphene quantum dots (GQD) have captured the substantial attention of nanotechnology due to their unique optical and magnetic properties [16][17][18][19][20][21][22][23][24][25][26][27][28][29] . The new element here is the finite-size electron confinement, resulted in opening of the energy gap for the bulk delocalized electronic states in the vicinity of Dirac point [16][17][18]21,22,25 .…”

Section: Introductionmentioning

confidence: 99%

“…This gap, however can be filled by the energy level of novel electronic states, localized in the vicinity of the sample boundary [16][17][18] . For nanoscopic and even for mesoscopic clusters these edge states can play the decisive role in electronic and magnetic properties of the flakes [18][19][20]28,29 . The situation can drastically depend on size and shape of the clusters.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Electronic and magnetic properties of graphite quantum dots

Abdelsalam¹,

Espinosa-Ortega

Luk’yanchuk

2015

Low Temperature Physics

View full text Add to dashboard Cite

We study the electronic and magnetic properties of multilayer quantum dots (MQDs) of graphite in the nearest-neighbor approximation of tight-binding model. We calculate the electronic density of states and orbital susceptibility of the system as function of the Fermi level location. We demonstrate that properties of MQD depend strongly on the shape of the system, on the parity of the layer number and on the form of the cluster edge. The special emphasis is given to reveal the new properties with respect to the monolayer graphene quantum dots (GQD). The most interesting results are obtained for the triangular MQD with zig-zag edge at near-zero energies. The asymmetrically smeared multi-peak feature is observed at Dirac point within the size-quantized energy gap region, where monolayer graphene flakes demonstrate the highly-degenerate zero-energy state. This feature, provided by the edge-localized electronic states results in the splash-wavelet behavior in diamagnetic orbital susceptibility as function of energy.

show abstract

Planar Alignment of Graphene Sheets by a Rotating Magnetic Field for Full Exploitation of Graphene as a 2D Material

Lin

Yang

Niu

et al. 2018

Adv Funct Materials

View full text Add to dashboard Cite

Planar alignment of disc-like nanomaterials is required to transfer their superior anisotropic properties from microscopic individual structures to macroscopic collective assemblies. However, such alignment by electrical or magnetic field is challenging due to their additional degrees of orientational freedom compared to that of rod-like nanostructures. Here, the realization of planar alignment of suspended graphene sheets using a rotating magnetic field produced by a pair of small NdFeB magnets and subsequent demonstration of high optical anisotropy and potential novel device applications is reported. Compared to partially aligned sheets with a static magnetic field, planar aligned graphene suspensions exhibit a near-perfect order parameter, much higher birefringence and anisotropic absorption/transmission. A unique feature of discotic nanomaterial assemblies is that the observed order parameter and optical property can vary from isotropic to partial and complete alignment depending on the experimental configuration. By immobilizing and patterning aligned graphene in a UV-curable polymer resin, we further demonstrated an all-graphene permanent display, which exhibits wide-angle, high dark-bright contrast in either transmission or reflection mode without any polarizing optics. The ability to control and pattern graphene orientation in all three dimensions opens up new exploration and broad device applications of graphene.

show abstract

Orbital magnetism of graphene flakes

Cited by 54 publications

References 71 publications

Orbital magnetism of graphene nanostructures: Bulk and confinement effects

Orbital magnetism of graphene nanostructures: Bulk and confinement effects

Electronic and magnetic properties of graphite quantum dots

Planar Alignment of Graphene Sheets by a Rotating Magnetic Field for Full Exploitation of Graphene as a 2D Material

Contact Info

Product

Resources

About