Charge transport and inhomogeneity near the minimum conductivity point in graphene

Cho, Sungjae; Fuhrer, Michael S.

doi:10.1103/physrevb.77.081402

Cited by 168 publications

(167 citation statements)

References 25 publications

Supporting

Mentioning

148

Contrasting

Order By: Relevance

“…Thus the mechanism of strong positive magnetoresistance analyzed in this work is essentially different from that based on an assumption of macroscopic inhomogeneities that were discussed as a possible source of magnetoresistance in Refs. [23,24]. Further experimental studies of magnetoresistance in high-mobility graphene samples (including the dependence on the sample width) would be of great interest.…”

Section: Discussionmentioning

confidence: 99%

“…We show that at μ = 0, the three hydrodynamic modes are strongly affected by the sample boundaries and quasiparticle recombination, leading to strong positive magnetoresistance, the experimentally observed effect, see Refs. [23][24][25]28].…”

Section: Magnetoresistance Of Monolayer Graphenementioning

confidence: 99%

“…However, at the charge neutrality point and in the degenerate limit, the equations simplify allowing for an analytic solution. In the former case, we focus on the issue of magnetoresistance, a subject of considerable experimental interest [23][24][25][26][27][28][29]. In particular, we demonstrate the appearance of the linear magnetoresistance in moderately strong, classical magnetic fields in monolayer graphene [30].…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Hydrodynamics in graphene: Linear-response transport

et al. 2015

View full text Add to dashboard Cite

We develop a hydrodynamic description of transport properties in graphene-based systems, which we derive from the quantum kinetic equation. In the interaction-dominated regime, the collinear scattering singularity in the collision integral leads to fast unidirectional thermalization and allows us to describe the system in terms of three macroscopic currents carrying electric charge, energy, and quasiparticle imbalance. Within this "three-mode" approximation, we evaluate transport coefficients in monolayer graphene as well as in double-layer graphene-based structures. The resulting classical magnetoresistance is strongly sensitive to the interplay between the sample geometry and leading relaxation processes. In small, mesoscopic samples, the macroscopic currents are inhomogeneous, which leads to a linear magnetoresistance in classically strong fields. Applying our theory to double-layer graphene-based systems, we provide a microscopic foundation for a phenomenological description of giant magnetodrag at charge neutrality and find the magnetodrag and Hall drag in doped graphene.

show abstract

Section: Discussionmentioning

confidence: 99%

Section: Magnetoresistance Of Monolayer Graphenementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Hydrodynamics in graphene: Linear-response transport

et al. 2015

View full text Add to dashboard Cite

show abstract

“…For example, the carrier mobility in graphene deposited on a substrate such as Si/SiO 2 deteriorates due to trapped charges in the oxide or to contaminants that get trapped at the graphene-substrate interface during fabrication. The substrate-induced charge inhomogeneity is particularly deleterious near the DP where screening is weak, 14,15 leading to reduced carrier mobility there. In addition, the atomic roughness of the substrate introduces short range scattering centers and may contribute to quench-condensation of ripples within the graphene layer 16 .…”

mentioning

confidence: 99%

Approaching ballistic transport in suspended graphene

et al. 2008

View full text Add to dashboard Cite

The recent discovery of methods to isolate graphene 1-3 , a one-atom-thick layer of crystalline carbon, has raised the possibility of a new class of nano-electronics devices based on the extraordinary electrical transport and unusual physical properties 4,5 of this material. However, the experimental realization of devices displaying these properties was, until now, hampered by the influence of the ambient environment, primarily the substrate. Here we report on the fabrication of Suspended Graphene (SG) devices and on studies of their electrical transport properties. In these devices, environmental disturbances were minimized allowing unprecedented access to the intrinsic properties of graphene close to the Dirac Point (DP) where the energy dispersion of the carriers and their density-of-states vanish linearly giving rise to a range of exotic physical properties. We show that charge inhomogeneity is reduced by almost one order of magnitude compared to that in Non-Suspended Graphene (NSG) devices. Moreover, near the DP, the mobility exceeds 100,000 cm 2 /Vs, approaching theoretical predictions for evanescent transport in the ballistic model. The low energy excitation spectrum of graphene mimics relativistic particles -massless Dirac fermions (DF) -with an electron-hole symmetric conical energy dispersion and .vanishing density of states at the DP. Such unusual spectrum is expected to produce 1 novel electronic properties such as negative index of refraction 6 , specular Andreev reflections at graphene-superconductor junctions 7,8 , evanescent transport 9 , anomalous phonon softening 10 , etc. A basic assumption behind these intriguing predictions is that the graphene layer is minimally affected by interactions with the environment. However in reality the environment 11,12 and in particular the substrate 13 , can be quite invasive for such ultra-thin films. For example, the carrier mobility in graphene deposited on a substrate such as Si/SiO 2 deteriorates due to trapped charges in the oxide or to contaminants that get trapped at the graphene-substrate interface during fabrication. The substrate-induced charge inhomogeneity is particularly deleterious near the DP where screening is weak, 14,15 leading to reduced carrier mobility there. In addition, the atomic roughness of the substrate introduces short range scattering centers and may contribute to quench-condensation of ripples within the graphene layer 16 .In order to eliminate substrate induced perturbations, graphene films were suspended from Au/Ti contacts to bridge over a trench in a SiO 2 substrate. In contrast to prior realizations of suspended graphene 17,18 which did not provide electrical contacts for transport measurements, the SG devices described here incorporate multiple electrodes that allow 4-lead transport measurements. The SG devices employed here were fabricated from conventional NSG devices using wet chemical etching (see supporting online material). In a typical SG device, shown in Figure 1b, the graphene layer is suspended from the voltage l...

show abstract

“…The sample dependence of the values of the quantum Hall data is in a general sense due to the removal of contamination after device preparation. [35,36,37,39] Because Zhang, et al, were able to clean the graphene Hall structure, they were the first to observe the quantum Hall effect in graphene. [35] The resistivity of single layer graphene has a sharp peak at the charge neutrality point (Vg ~0) and zero magnetic field.…”

Section: Ns=ib/q\v^\mentioning

confidence: 99%

Metrology for Emerging Materials, Devices, and Structures: The Example of Graphene

Diebold¹

2009

AIP Conference Proceedings

View full text Add to dashboard Cite

Charge transport and inhomogeneity near the minimum conductivity point in graphene

Cited by 168 publications

References 25 publications

Hydrodynamics in graphene: Linear-response transport

Hydrodynamics in graphene: Linear-response transport

Approaching ballistic transport in suspended graphene

Metrology for Emerging Materials, Devices, and Structures: The Example of Graphene

Contact Info

Product

Resources

About