Two-terminal quantized conductance in inhomogeneous graphene

Liao, Zhi-Min; Han, Binghong; Zhou, Yang-Bo; Yu, Dapeng

doi:10.1016/j.physleta.2010.06.017

Cited by 3 publications

(5 citation statements)

References 25 publications

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“…In an inhomogeneous system, the MR is dominated by the mobility fluctuations (∆µ) and the average mobility µ . Our previous investigation reveals two-terminal quantized conductance in the sample by sweeping gate voltage at a magnetic field above 5 T, indicating that a p-n junction may exist in this sample [13]. The inhomogeneities of carrier type and carrier density can result in mobility fluctuations.…”

mentioning

confidence: 74%

“…Graphene, a gapless 2D material with very low carrier effective mass, has linear dispersion relation and it can therefore easily meet the criterion ω c k B T at low temperature [10,11]. On the other hand, both experiments and theories indicate that carrier density in graphene is inhomogeneous, giving rise to a nonuniform spatial distribution of the carrier mobility (that is mobility fluctuations) [12,13]. Consequently, graphene is a perfect candidate to investigate both quantum and classical linear MR.…”

mentioning

confidence: 99%

“…Graphene samples were fabricated by mechanical exfoliation of graphene pieces onto a Si substrate with a 300 nm thick SiO 2 layer. Details of device fabrication and a scanning electron microscopy image of the two-terminal graphene device studied in this work were described elsewhere [13]. Previous observation of two-terminal quantized conductance suggests that the contact resistance can be ignored and the sample has spatial inhomogeneity [13].…”

mentioning

confidence: 99%

“…Details of device fabrication and a scanning electron microscopy image of the two-terminal graphene device studied in this work were described elsewhere [13]. Previous observation of two-terminal quantized conductance suggests that the contact resistance can be ignored and the sample has spatial inhomogeneity [13]. The graphene sheet was contacted by two metal electrodes with a conductive channel of ∼ 7 µm in length and ∼ 2 µm in width.…”

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confidence: 99%

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Observation of both classical and quantum magnetoresistance in bilayer graphene

Liao

Zhou

et al. 2011

EPL

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Magnetoresistance (MR) in bilayer graphene was experimentally investigated by varying magnetic-field strength. A transition from classical MR (superlinear dependence (B 4/3 )) to quantum MR (Shubnikov-de Haas oscillations) was observed at a magnetic field of about 10 T. The superlinear MR dependence is described using a classical route by considering the large inhomogenous mobility spatial distribution of charge carriers. Our experimental results may help to provide a clear physical picture of the magneto-transport properties of inhomogenous graphene.

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confidence: 74%

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confidence: 99%

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confidence: 99%

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confidence: 99%

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Observation of both classical and quantum magnetoresistance in bilayer graphene

Liao

Zhou

et al. 2011

EPL

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“…Consequently, the transport of carriers from electron (hole) doped terminals to hole (electron) doped terminals is facilitated by disorder as required by the band selective rule. Very recently, Liao et al have studied the quantized conductance plateau in inhomogeneous bilayer graphene in the quantum Hall regime and they found the anomalous quantized conductance plateau as a result of mixture quantum states from different Landau levels [15]. Klein tunneling, an effect first discovered in the field of high energy physics, is an important ingredient for electron transport in the graphene p-n junction.…”

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confidence: 99%

Transport properties of monolayer and bilayer graphene p–n junctions with charge puddles in the quantum Hall regime

Cheng

2010

J. Phys.: Condens. Matter

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Recent experiments have confirmed that the electron-hole inhomogeneity in graphene is a new type of charge disorder. Motivated by such confirmation, we theoretically study the transport properties of a monolayer graphene (MLG) based p-n junction and a bilayer graphene (BLG) p-n junction in the quantum Hall regime where electron-hole puddles are considered. By using the non-equilibrium Green function method, both the current and conductance are obtained. We find that, in the presence of the electron-hole inhomogeneity, the lowest quantized conductance plateau at e(2)/h emerges in the MLG p-n junction under very small charge puddle disorder strength. For a BLG p-n junction, however, the conductance in the p-n region is enhanced with charge puddles, and the lowest quantized conductance plateau emerges at 2e(2)/h. Besides, when an ideal quantized conductance plateau is formed for a MLG p-n junction, the universal conductance fluctuation is found to be 2e(2)/3h. Furthermore, we also investigate the influence of Anderson disorder on such p-n junctions and the comparison and discussion are given accordingly. To compare the two models with different types of disorder, we investigate the conductance distribution specially. Finally the influence of disorder strength on the conductance of a MLG p-n junction is investigated.

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Enhanced Magnetoresistance Effect in Graphene Coupled to a Ferromagnetic Oxide with Charge Orbital Ordering

Fan¹,

Coileáin²,

Arora³

et al. 2022

SPIN

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In this paper, we fabricated graphene/Fe3O4 heterostructure devices by stacking monolayer graphene on magnetite (Fe3O4) substrate and investigated their magneto-transport properties. Interestingly, graphene/Fe3O4 heterostructure devices exhibit a giant magnetoresistance (MR) of 70% at a low magnetic field of 0.65[Formula: see text]T and at 11[Formula: see text]K, which is three times greater than that of graphene on SiO2. Based on standard two-fluid model and LDA[Formula: see text]U simulation, we showed that the observed enhanced MR effect is due to the increased disorder in graphene induced through the charge polarization via the alignment of C atoms of graphene over the charge ordered B-site cations of Fe3O4. Our results demonstrate a potential way to enhance graphene MR effect through coupling graphene with a suitable substrate with charge orbital ordering.

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Two-terminal quantized conductance in inhomogeneous graphene

Cited by 3 publications

References 25 publications

Observation of both classical and quantum magnetoresistance in bilayer graphene

Observation of both classical and quantum magnetoresistance in bilayer graphene

Transport properties of monolayer and bilayer graphene p–n junctions with charge puddles in the quantum Hall regime

Enhanced Magnetoresistance Effect in Graphene Coupled to a Ferromagnetic Oxide with Charge Orbital Ordering

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