Magnetic-field-induced charge redistribution in disordered graphene double quantum dots

Chiu, K. L.; Connolly, M. R.; Cresti, Alessandro; Griffiths, J. P.; Jones, G. A. C.; Smith, Charles G.

doi:10.1103/physrevb.92.155408

Cited by 7 publications

(10 citation statements)

References 33 publications

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“…For instance, magnetic properties of graphene nanoribbons are found to be strongly dependent of long-range impurities [40]. In addition, the role of electron-hole puddles on the formation of Landau levels in a graphene double quantum dot was investigated experimentally by K. L. Chiu et al [41].…”

Section: Introductionmentioning

confidence: 99%

Effects of long-range disorder and electronic interactions on the optical properties of graphene quantum dots

2017

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We theoretically investigate the effects of long-range disorder and electron-electron interactions on the optical properties of hexagonal armchair graphene quantum dots consisting of up to 10806 atoms. The numerical calculations are performed using a combination of tight-binding, mean-field Hubbard and configuration interaction methods. Imperfections in the graphene quantum dots are modelled as a long-range random potential landscape, giving rise to electron-hole puddles. We show that, when the electron-hole puddles are present, tight-binding method gives a poor description of the low-energy absorption spectra compared to meanfield and configuration interaction calculation results. As the size of the graphene quantum dot is increased, the universal optical conductivity limit can be observed in the absorption spectrum. When disorder is present, calculated absorption spectrum approaches the experimental results for isolated monolayer of graphene sheet.

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Section: Introductionmentioning

confidence: 99%

Effects of long-range disorder and electronic interactions on the optical properties of graphene quantum dots

2017

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“…Main observations of graphene single quantum dots (GSQDs) [1] Observation of excited states [2] Charge detection [3,60] Fock-Darwin spectrum in the fewelectron and many-electron regimes [85] Zeeman splitting of spin states [89] First suspended GQDs [89,90,132] Bilayer GQDs defined by top gates [84,101] High-frequency gate manipulation on GQDs [93] GQDs defined via strain engineering References Main observations of graphene double quantum dots (GDQDs) [86,87,117] Observation of excited states [87] Zeeman splitting [87,133] Bilayer graphene double dot [86] GDQDs defined by gated GNRs [134] Electron-phonon coupling [119] Metal gate tuning [88] Charge pumping [127] Charge redistribution in magnetic fields [121] RF sensing of the number of charges…”

Section: Table I References For the Main Observations Referencesmentioning

confidence: 99%

“…Fig. 24(a) shows the evolution of the charge stability diagram of a large GDQD (200 nm in diameter) for applied perpendicular magnetic fields ranging from 4 to 10 T [127]. The field-dependent changes in the dimensions of the honeycomb (highlighted by the dotted hexagonal outlines) indicate the variations in the capacitances C g1 and C g2 and thus the changes in the charging energies of both dots [see Eqs.…”

Section: Coulomb Blockade and Magneto-transportmentioning

confidence: 99%

“…A schematic model shown in Fig. 24(b), (c) and (d) serve as a qualitative explanation for this observation [127]. Consider a varying background potential V in a model QD, as shown in Fig.…”

Section: Coulomb Blockade and Magneto-transportmentioning

confidence: 99%

“…Main observations of graphene double quantum dots (GDQDs) [86,87,117] Observation of excited states [87] Zeeman splitting [87,133] Bilayer graphene double dot [86] GDQDs defined by gated GNRs [134] Electron-phonon coupling [119] Metal gate tuning [88] Charge pumping [127] Charge redistribution in magnetic fields [121] RF sensing of the number of charges…”

Section: Charge Pumpingmentioning

confidence: 99%

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Single-electron transport in graphene-like nanostructures

Chiu

2017

Physics Reports

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Two-dimensional (2D) materials for their versatile band structures and strictly 2D nature have attracted considerable attention over the past decade. Graphene is a robust material for spintronics owing to its weak spin-orbit and hyperfine interactions, while monolayer transition metal dichalcogenides (TMDs) possess a Zeeman effect-like band splitting in which the spin and valley degrees of freedom are nondegenerate. The surface states of topological insulators (TIs) exhibit a spinmomentum locking that opens up the possibility of controlling the spin degree of freedom in the absence of an external magnetic field. Nanostructures made of these materials are also viable for use in quantum computing applications involving the superposition and entanglement of individual charge and spin quanta. In this article, we review a selection of transport studies addressing the confinement and manipulation of charges in nanostructures fabricated from various 2D materials. We supply the entry-level knowledge for this field by first introducing the fundamental properties of 2D bulk materials followed by the theoretical background relevant to the physics of nanostructures. Subsequently, a historical review of experimental development in this field is presented, from the early demonstration of graphene nanodevices on SiO2 substrate to more recent progress in utilizing hexagonal boron nitride to reduce substrate disorder. In the second part of this article, we extend our discussion to TMDs and TI nanostructures. We aim to outline the current challenges and suggest how future work will be geared towards developing spin qubits in 2D materials.

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