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We consider quantum interference effects in carrier and photocurrent excitation in graphene using coherent electromagnetic field components at frequencies $\omega$ and $2\omega$. The response of the material at the fundamental frequency…

Mesoscale and Nanoscale Physics · Physics 2014-09-24 J. Rioux , J. E. Sipe , Guido Burkard

Recent advances in strain engineering at the nanoscale have shown the feasibility to modulate the properties of graphene. Although the electron-phonon (e-ph) coupling and Kohn anomalies in graphene define the phonon branches contributing to…

Mesoscale and Nanoscale Physics · Physics 2016-08-02 M. E. Cifuentes-Quintal , O. de la Peña-Seaman , R. Heid , R. de Coss , K. -P. Bohnen

We report the Raman spectroscopy of 12C/13C graphene isotope superlattices synthesized by chemical vapour deposition. At large periods the Raman spectra corresponds to the sum of the bulk 12C and 13C contributions. However, at small periods…

Materials Science · Physics 2021-01-04 Eric Whiteway , Martin Lee , Michael Hilke

In contrary to the widely reported single and symmetric peak feature of G' (or 2D) band in Raman spectrum of graphene, we herein report the observation of splitting in G' band in free standing graphene. Our experimental findings provide a…

Materials Science · Physics 2015-06-04 Zhiqiang Luo , Chunxiao Cong , Jun Zhang , Qihua Xiong , Ting Yu

Using Raman spectroscopy and transport measurements we investigate thin epitaxial films of Y{1-x}(Pr,Ca)xBa2Cu3O{6+y}. We explore the electronic Raman responses obtained after subtraction of phononic excitations, and the 2Delta peaks that…

Superconductivity · Physics 2017-09-27 A. Bock

This paper reports the experimental determination of the phase-breaking length L of conduction electrons in graphene using Raman spectroscopy. Based on the double-resonance model, we extract L from the spatial dependence of the D band…

Materials Science · Physics 2008-02-27 Luiz Gustavo Cancado , Ryan Beams , Lukas Novotny

The effect of grain boundaries and wrinkles on the electrical properties of polycrystalline graphene is pronounced. Here we investigate the stitching between grains of polycrystalline graphene, specifically, overlapping of layers at the…

Materials Science · Physics 2014-06-09 Rahul Rao , Neal Pierce , Avetik R. Harutyunyan

We theoretically investigate the double-resonance Raman spectrum of monolayer graphene down to infrared laser excitation energies. By using first-principles density functional theory calculations, we improve upon previous theoretical…

Mesoscale and Nanoscale Physics · Physics 2025-05-21 Lorenzo Graziotto , Francesco Macheda , Thibault Sohier , Matteo Calandra , Francesco Mauri

In this paper, the effect of B and N doping on the phonon induced thermal conductivity of graphene has been investigated. This study is important when one has to evaluate the usefulness of electronic properties of B and N doped graphene. We…

The scattering of lattice excitations (phonons) with the photoexcited charge carriers is of a major concern in optoelectronic devices. Here, the resonant Raman scattering will be utilized to study an exciton-phonon interaction in GaN…

Gate-modulated low-temperature Raman spectra reveal that the electric field effect (EFE), pervasive in contemporary electronics, has marked impacts on long wavelength optical phonons of graphene. The EFE in this two dimensional honeycomb…

Mesoscale and Nanoscale Physics · Physics 2009-11-11 Jun Yan , Yuanbo Zhang , Philip Kim , Aron Pinczuk

We perform a phenomenological analysis of the problem of the electronic doping of a graphene sheet by deposited transition metal atoms, which aggregate in clusters. The sample is placed in a capacitor device such that the electronic doping…

Strongly Correlated Electrons · Physics 2015-03-19 Jaime E. Santos , Nuno M. R. Peres , Joao M. B. Lopes dos Santos , Antonio H. Castro Neto

We report an atomically-precise integration of individual nitrogen (N) dopant as an in-plane artificial nucleus in a graphene device by atomic implantation to probe its gate-tunable quantum states and correlation effects. The N dopant…

We obtain analytical expressions for the electron self-energy and the electron-phonon coupling in electron-doped graphene using electron-phonon matrix elements extracted from density functional theory simulations. From the electron…

Superconductivity · Physics 2009-11-13 Matteo Calandra , Francesco Mauri

Graphene has many unique properties that make it an ideal material for fundamental studies as well as for potential applications. Here we review the recent results on the Raman spectroscopy and imaging of graphene. Raman spectroscopy and…

Materials Science · Physics 2008-10-17 Zhen hua Ni , Ying ying Wang , Ting Yu , Ze xiang Shen

Raman spectroscopic studies of graphene have attracted much interest. The G-band Raman intensity of a single layer graphene on Si substrate with 300 nm SiO2 capping layer is surprisingly strong and is comparable to that of bulk graphite. To…

Materials Science · Physics 2009-11-13 Yingying Wang , Zhenhua Ni , Zexiang Shen , Haomin Wang , Yihong Wu

Few-layer graphene possesses low-energy carriers which behave as massive fermions, exhibiting intriguing properties in both transport and light scattering experiments. Lowering the excitation energy of resonance Raman spectroscopy down to…

High-frequency performance of graphene field-effect transistors (GFETs) with boron-nitride gate dielectrics is investigated. Devices show saturating IV characteristics and fmax values as high as 34 GHz at 600-nm channel length. Bias…

Mesoscale and Nanoscale Physics · Physics 2011-12-14 I. Meric , C. R. Dean , S. -J. Han , L. Wang , K. A. Jenkins , J. Hone , K. L. Shepard

Ab-initio density functional perturbation theory (DFPT) has been employed to study thermodynamical properties of pure and doped graphene sheet and the results have been compared with available theoretical and experimental data. The…

Mesoscale and Nanoscale Physics · Physics 2020-05-22 Sarita Mann , Pooja Rani , Ranjan Kumar , Girija S. Dubey , V. K. Jindal

We use Raman spectroscopy to show that exposing few-layer graphene to extreme ultraviolet (EUV, 13.5 nm) radiation, i.e. relatively low photon energy, results in an increasing density of defects. Furthermore, exposure to EUV radiation in a…

Materials Science · Physics 2013-08-27 A. Gao , P. J. Rizo , E. Zoethout , L. Scaccabarozzi , C. J. Lee , V. Banine , F. Bijkerk