Shot noise in lithographically patterned graphene nanoribbons

Tan, Zhongchao; Puska, Antti; Nieminen, Tero; Duerr, Fabian; Gould, C.; Molenkamp, L. W.; Trauzettel, Björn; Hakonen, Pertti

doi:10.1103/physrevb.88.245415

Cited by 14 publications

(17 citation statements)

References 45 publications

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“…It is found that the Fano factors at 0 T are ∼0.5 far from the charge neutral point and they are enhanced around the charge neutral point. Among several experimental works on this topic 21 22 23 , our result agrees with that for graphene nanoribbon 23 , which reported F ∼0.4. According to theoretical studies 24 25 , the Fano factors at 0 T strongly depend on the disorder strength, which could explain the present results.…”

Section: Resultssupporting

confidence: 89%

Edge mixing dynamics in graphene p–n junctions in the quantum Hall regime

et al. 2015

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Massless Dirac electron systems such as graphene exhibit a distinct half-integer quantum Hall effect, and in the bipolar transport regime co-propagating edge states along the p–n junction are realized. Additionally, these edge states are uniformly mixed at the junction, which makes it a unique structure to partition electrons in these edge states. Although many experimental works have addressed this issue, the microscopic dynamics of electron partition in this peculiar structure remains unclear. Here we performed shot-noise measurements on the junction in the quantum Hall regime as well as at zero magnetic field. We found that, in sharp contrast with the zero-field case, the shot noise in the quantum Hall regime is finite in the bipolar regime, but is strongly suppressed in the unipolar regime. Our observation is consistent with the theoretical prediction and gives microscopic evidence that the edge states are uniquely mixed along the p–n junction.

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Section: Resultssupporting

confidence: 89%

Edge mixing dynamics in graphene p–n junctions in the quantum Hall regime

et al. 2015

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“…The measured conductivities correspond to a field effect mobility of cm 2 /Vs, which is by a factor of two smaller than in the graphene cross experiments of ref. 25 . Some asymmetry in conductances is observed at and V. However, the asymmetry in these regions is bias dependent and its influence on cross correlations becomes reduced by using a fixed current-level correlation determination if necessary (For a linear cross-shaped conductor, when switching to measurement configuration C, the currents at terminals 1 and 3 double from the single source configurations A and B.…”

Section: Resultsmentioning

confidence: 99%

Hanbury-Brown and Twiss exchange and non-equilibrium-induced correlations in disordered, four-terminal graphene-ribbon conductor

Tan

Elo

Puska

et al. 2018

Sci Rep

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We have investigated current-current correlations in a cross-shaped conductor made of graphene. The mean free path of charge carriers is on the order of the ribbon width which leads to a hybrid conductor where there is diffusive transport in the device arms while the central connection region displays near ballistic transport. Our data on auto and cross correlations deviate from the predictions of Landauer-Büttiker theory, and agreement can be obtained only by taking into account contributions from non-thermal electron distributions at the inlets to the semiballistic center, in which the partition noise becomes strongly modified. The experimental results display distinct Hanbury – Brown and Twiss (HBT) exchange correlations, the strength of which is boosted by the non-equilibrium occupation-number fluctuations internal to this hybrid conductor. Our work demonstrates that variation in electron coherence along atomically-thin, two-dimensional conductors has significant implications on their noise and cross correlation properties.

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“…46,62,96,158,160,162,[164][165][166]174,176,186,195,196,[199][200][201][202][203][204][205][206]230,and 238) with exception of the previously highlighted experiments and Refs. 157,187, and 211 that did not provide sufficiently high resolution data to make a clear statement.…”

Section: B Observation Of Coulomb Blockadementioning

confidence: 90%

“…From all references presenting data at low temperature over a large range of charge carrier densities (see Refs. 46,56,61,62,96,[156][157][158][159][160]162,[164][165][166]168,173,174,176,180,[186][187][188][189]191,[194][195][196][197][198][199][200][201][202][203][204][205][206]210,211,213,[217][218][219]227,229,233,and 237), most agree that for sufficiently narrow ribbons at sufficiently low temperatures, transport is strongly suppressed. Typically, the conductance decreases with increasing gate voltage until at a certain point conductance is nearly completely suppressed.…”

Section: A Suppressed Conductancementioning

confidence: 99%

Localized charge carriers in graphene nanodevices

Bischoff

Varlet

Simonet

et al. 2015

Applied Physics Reviews

100

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Graphene—two-dimensional carbon—is a material with unique mechanical, optical, chemical, and electronic properties. Its use in a wide range of applications was therefore suggested. From an electronic point of view, nanostructured graphene is of great interest due to the potential opening of a band gap, applications in quantum devices, and investigations of physical phenomena. Narrow graphene stripes called “nanoribbons” show clearly different electronical transport properties than micron-sized graphene devices. The conductivity is generally reduced and around the charge neutrality point, the conductance is nearly completely suppressed. While various mechanisms can lead to this observed suppression of conductance, disordered edges resulting in localized charge carriers are likely the main cause in a large number of experiments. Localized charge carriers manifest themselves in transport experiments by the appearance of Coulomb blockade diamonds. This review focuses on the mechanisms responsible for this charge localization, on interpreting the transport details, and on discussing the consequences for physics and applications. Effects such as multiple coupled sites of localized charge, cotunneling processes, and excited states are discussed. Also, different geometries of quantum devices are compared. Finally, an outlook is provided, where open questions are addressed.

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Shot noise in lithographically patterned graphene nanoribbons

Cited by 14 publications

References 45 publications

Edge mixing dynamics in graphene p–n junctions in the quantum Hall regime

Edge mixing dynamics in graphene p–n junctions in the quantum Hall regime

Hanbury-Brown and Twiss exchange and non-equilibrium-induced correlations in disordered, four-terminal graphene-ribbon conductor

Localized charge carriers in graphene nanodevices

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