arXiv 0804.22532008-04cond-mat.mes-hall

Density inhomogeneity driven percolation metal-insulator transition and dimensional crossover in graphene nanoribbons

S. Adam, S. Cho, M. S. Fuhrer, S. Das Sarma

备注：: Revised version published in Phys. Rev. Lett. 101, 046404 (2008)
发表信息：: Phys. Rev. Lett. 101, 046404 (2008)
DOI：: 10.1103/PhysRevLett.101.046404

英文摘要：

Transport in graphene nanoribbons with an energy gap in the spectrum is considered in the presence of random charged impurity centers. At low carrier density, we predict and establish that the system exhibits a density inhomogeneity driven two dimensional metal-insulator transition that is in the percolation universality class. For very narrow graphene nanoribbons (with widths smaller than the disorder induced length-scale), we predict that there should be a dimensional crossover to the 1D percolation universality class with observable signatures in the transport gap. In addition, there should be a crossover to the Boltzmann transport regime at high carrier densities. The measured conductivity exponent and the critical density are consistent with this percolation transition scenario.

机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。

阅读原文

阅读 PDF ↗

arXiv 页面 ↗HTML 原文 ↗

本文内容

英文摘要相关论文

机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。

继续探索

相关论文

From diffusive to ballistic transport in etched graphene constrictions and nanoribbons

Graphene nanoribbons and constrictions are envisaged as fundamental components of future carbon-based nanoelectronic and spintronic devices. At nanoscale, electronic effects in these devices depend heavily on the dimensions of the active channel and the nature of edges. Hence, controlling both these parameters is crucial to understand the physics in such systems. This review is about the recent progress in the fabrication of graphene nanoribbons and constrictions in terms of low temperature quantum transport. In particular, recent advancements using encapsulated graphene allowing for quantized…

2017-06-29cond-mat.mes-hall

Field Effect Transistors based on Networks of Highly Aligned, Chemically Synthesized N=7 Armchair Graphene Nanoribbons

We report on the experimental demonstration and electrical characterization of N = 7 armchair graphene nanoribbon (7-AGNR) field effect transistors. The back-gated transistors are fabricated from atomically precise and highly aligned 7-AGNRs, synthesized with a bottom-up approach. The large area transfer process holds the promise of scalable device fabrication with atomically precise nanoribbons. The channels of the FETs are approximately 30 times longer than the average nanoribbon length of 30 nm to 40 nm. The density of the GNRs is high, so that transport can be assumed well-above the percol…

2018-03-19cond-mat.mes-hall

Kerr nonlinearity and plasmonic bistability in graphene nanoribbons

We theoretically examine the role of Kerr nonlinearities for graphene plasmonics in nanostructures, specifically in nanoribbons. The nonlinear Kerr interaction is included semiclassically in the intraband approximation. The resulting electromagnetic problem is solved numerically by self-consistent iteration with linear steps using a real-space discretization. We derive a simple approximation for the resonance shifts in general graphene nanostructures, and obtain excellent agreement with numerics for moderately high field strengths. Near plasmonic resonances the nonlinearities are strongly enha…

2015-06-09cond-mat.mes-hall

Conductance across strain junctions in graphene nanoribbons

To address the robustness of the transport gap induced by locally strained regions in graphene nanostructures, the effect of disorder and smoothness of the interface region is investigated within the Landauer-Büttiker formalism. The electronic conductance across strained junctions and barriers in graphene nanoribbons is calculated numerically, with and without various types of disorder, and comparing smooth and sharp strain junctions. A smooth strain barrier in graphene is seen to be generically as efficient in suppressing transport at low densities as a sharp one, and the critical density (or…

2013-10-30cond-mat.mes-hall

Transport and percolation in a low-density high-mobility two-dimensional hole system

We present a study of the temperature and density dependence of the resistivity of an extremely high quality two-dimensional hole system grown on the (100) surface of GaAs. For high densities in the metallic regime ($p\agt 4 \times 10^{9}$ cm$^{-2}$), the nonmonotonic temperature dependence ($\sim 50-300$ mK) of the resistivity is consistent with temperature dependent screening of residual impurities. At a fixed temperature of $T$= 50 mK, the conductivity vs. density data indicates an inhomogeneity driven percolation-type transition to an insulating state at a critical density of $3.8\times 10…

2007-10-18cond-mat.mes-hall

2D Metal-Insulator transition as a percolation transition

By carefully analyzing the low temperature density dependence of 2D conductivity in undoped high mobility n-GaAs heterostructures, we conclude that the 2D metal-insulator transition in this system is a density inhomogeneity driven percolation transition due to the breakdown of screening in the random charged impurity disorder background. In particular, our measured conductivity exponent of $\sim 1.4$ approaches the 2D percolation exponent value of 4/3 at low temperatures and our experimental data are inconsistent with there being a zero-temperature quantum critical point in our system.

2004-06-25cond-mat.dis-nncond-mat.mes-hall

更多相关论文收起更多论文

The Observation of Percolation-Induced 2D Metal-Insulator Transition in a Si MOSFET

By analyzing the temperature ($T$) and density ($n$) dependence of the measured conductivity ($σ$) of 2D electrons in the low density ($\sim10^{11}$cm$^{-2}$) and temperature (0.02 - 10 K) regime of high-mobility (1.0 and 1.5 $\times 10^4$ cm$^2$/Vs) Si MOSFETs, we establish that the putative 2D metal-insulator transition is a density-inhomogeneity driven percolation transition where the density-dependent conductivity vanishes as $σ(n) \propto (n - n_p)^p$, with the exponent $p \sim 1.2$ being consistent with a percolation transition. The `metallic' behavior of $σ(T)$ for $n > n_p$ is shown to…

2009-05-18cond-mat.mes-hall

光致相变中自举渗流动力学的证据

Evidence for bootstrap percolation dynamics in a photo-induced phase transition

本研究通过时间分辨二次谐波实验和自举渗流模拟，揭示了Ca$_3$Ru$_2$O$_7$光致相变中特征时间非单调变化，证明介观不均匀性主导转变动力学。

2023-05-09cond-mat.mes-hallcond-mat.str-el

Density fluctuation effects on the exciton condensate in double layer graphene

We describe the robustness of an excitonic condensate in double layer graphene against layer density fluctuations and the associated charge inhomogeneity, and discuss the implications for observing the condensate under current experimental conditions. We solve the mean-field equations for a finite imbalance in the Fermi energies in each layer and utilize the results in two phenomenological models for inhomogeneity. We find that the stability of the excitonic condensate against density fluctuations is strongly dependent on the size of the excitonic gap, and that transport experiments (such as C…

2012-11-02cond-mat.dis-nncond-mat.mes-hall

外延石墨烯的Pb(111)岛均匀掺杂：磁输运研究

Homogeneous doping of epitaxial graphene by Pb(111) islands: A magnetotransport study

本研究通过磁输运实验发现，Pb(111)岛在石墨烯上均匀掺杂且不诱导Rashba自旋轨道耦合，与理论预测相反，并屏蔽缺陷降低谷间散射。

2025-02-27cond-mat.mes-hall