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Related papers: Raman Scattering at Pure Graphene Zigzag Edges

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It is demonstrated that measurements of positions of atoms scattered from a quasi-condensate in a Raman process provide information on the temperature of the parent cloud. In particular, the widths of the density and second order…

Quantum Gases · Physics 2013-01-28 T. Wasak , J. Chwedenczuk , P. Zin , M. Trippenbach

Graphene can at present be grown at large quantities only by the chemical vapor deposition method, which produces polycrystalline samples. Here, we describe a method for constructing realistic polycrystalline graphene samples for atomistic…

Materials Science · Physics 2012-05-28 Jani Kotakoski , Jannik C. Meyer

Band gap engineering in graphene may open the routes towards transistor devices in which electric current can be switched off and on at will. One may, however, ask if a semiconducting band gap alone is sufficient to quench the current in…

Mesoscale and Nanoscale Physics · Physics 2012-11-12 G. Tkachov , Martina Hentschel

Single- and few-layer MoS2 has recently gained attention as an interesting new material system for opto-electronics. Here, we report on scanning Raman measurements on few-layer MoS2 flakes prepared by exfoliation. We observe a Raman mode…

Materials Science · Physics 2012-09-19 G. Plechinger , S. Heydrich , J. Eroms , D. Weiss , Schüller , T. Korn

The pseudo-magnetic field generated by mechanical strain in graphene can have dramatic consequences on the behavior of electrons and holes. Here we show that pseudo-magnetic field fluctuations present in crumpled graphene can induce…

Creating defects in graphene by hydrogenation, either to achieve hydrogen chemisorption or partial etching, is a way to open an electronic band gap in graphene. Understanding the range of stability conditions of partially etched or…

We demonstrate insights into the three-dimensional structure of defects in graphene, in particular grain boundaries, obtained via a new approach from two transmission electron microscopy images recorded at different angles. The structure is…

We discuss various scattering mechanisms for Dirac fermions in single-layer graphene. It is shown that scattering on a short-range potential (due to, for example, neutral impurities) is mostly irrelevant for electronic quality of graphene,…

Mesoscale and Nanoscale Physics · Physics 2007-12-06 M. I. Katsnelson , A. K. Geim

In an ideal graphene sheet charge carriers behave as two-dimensional (2D) Dirac fermions governed by the quantum mechanics of massless relativistic particles. This has been confirmed by the discovery of a half-integer quantum Hall effect in…

Materials Science · Physics 2015-05-13 Yuanbo Zhang , Victor W. Brar , Caglar Girit , Alex Zettl , Michael F. Crommie

Zigzag edges of graphene nanostructures host localized electronic states that are predicted to be spin-polarized. However, these edge states are highly susceptible to edge roughness and interaction with a supporting substrate, complicating…

Confocal Raman spectroscopy is a versatile, non-invasive investigation tool and a major workhorse for graphene characterization. Here we show that the experimentally observed Raman 2D line width is a measure of nanometer-scale strain…

We investigate spin transport in diffusive graphene nanoribbons with both clean and rough zigzag edges, and long-range potential fluctuations. The long-range fields along the ribbon edges cause the local doping to come close to the charge…

Mesoscale and Nanoscale Physics · Physics 2014-03-31 Jan Bundesmann , Ming-Hao Liu , Inanc Adagideli , Klaus Richter

Raman scattering experiments from silver nanocrystals embedded in films of amorphous silica are reported. In addition to the low-frequency peak due to vibrational quadrupolar modes, a broadband is observed in the high-frequency range, with…

Condensed Matter · Physics 2007-05-23 H. Portales , E. Duval , L. Saviot , M. Fujii , M. Sumitomo , S. Hayashi

Immersing a mobile impurity in a quantum many-body environment can reveal fundamental properties of the background medium, hence providing a powerful probe of quantum matter. This approach is particularly intriguing when considering media…

Graphene nanoribbons (GNRs) are atomically precise stripes of graphene with tunable electronic properties, making them promising for room-temperature switching applications like field-effect transistors (FETs). However, challenges persist…

We present low-temperature Raman measurements on gate tunable graphene encapsulated in hexagonal boron nitride, which allows to study in detail the Raman G and 2D mode frequencies and line widths as function of the charge carrier density.…

Mesoscale and Nanoscale Physics · Physics 2023-02-15 Jens Sonntag , Kenji Watanabe , Takashi Taniguchi , Bernd Beschoten , Christoph Stampfer

We study the stability of filaments in equilibrium between gravity and internal as well as external pressure using the grid based AMR-code RAMSES. A homogeneous, straight cylinder below a critical line mass is marginally stable. However, if…

Solar and Stellar Astrophysics · Physics 2017-01-18 Matthias Gritschneder , Stefan Heigl , Andreas Burkert

Many of the proposed future applications of graphene require the controlled introduction of defects into its perfect lattice. Energetic ions provide one way of achieving this challenging goal. Single heavy ions with kinetic energies in the…

Materials Science · Physics 2010-09-27 S. Akcöltekin , H. Bukowska , T. Peters , O. Osmani , I. Monnet , I. Alzaher , B. Ban d'Etat , H. Lebius , M. Schleberger

The Raman $2D$-band -important for the analysis of graphene- shows a splitting for uniaxial strain. The splitting depends on the strength and direction of the applied strain and on the polarization of the incident and outgoing light. We…

Materials Science · Physics 2010-12-07 Marcel Mohr , Janina Maultzsch , Christian Thomsen

A central question in the field of graphene-related research is how graphene behaves when it is patterned at the nanometer scale with different edge geometries. Perhaps the most fundamental shape relevant to this question is the graphene…