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The temperature dependence of the mobility in suspended graphene samples is investigated. In clean samples, flexural phonons become the leading scattering mechanism at temperature $T \gtrsim 10\,\,$K, and the resistivity increases…

Although extensive experimental and theoretical works have been conducted to understand the ballistic and diffusive phonon transport in nanomaterials recently, direct observation of temperature and thermal nonequilibrium of different phonon…

Mesoscale and Nanoscale Physics · Physics 2017-05-17 Tianli Feng , Wenjun Yao , Zuyuan Wang , Jingjing Shi , Chuang Li , Bingyang Cao , Xiulin Ruan

We report on the temperature dependence of the anharmonic decay rate of zone-center (G mode) optical phonons in both single-walled carbon nanotubes and graphite. The measurements are performed using a pump-probe Raman scattering scheme with…

Materials Science · Physics 2011-06-09 Ioannis Chatzakis , Hugen Yan , Daohua Song , Stéphane Berciaud , Tony F. Heinz

In this work, we study the heat transfer from electron to phonon system within a five monolayer thin epitaxial Pb film on Si(111) upon fs-laser excitation. The response of the electron system is determined using time-resolved photoelectron…

Mesoscale and Nanoscale Physics · Physics 2023-12-08 M. Tajik , T. Witte , Ch. Brand , L. Rettig , B. Sothmann , U. Bovensiepen , M. Horn von Hoegen

The dispersion of electrons and phonons near the K point of bilayer graphene was investigated in a resonant Raman study using different laser excitation energies in the near infrared and visible range. The electronic structure was analyzed…

Mesoscale and Nanoscale Physics · Physics 2011-04-08 D. L. Mafra , L. M. Malard , S. K. Doorn , H. Htoon , J. Nilsson , A. H. Castro Neto , M. A. Pimenta

Time-resolved Raman spectroscopy has been applied to probe the anharmonic coupling and electron-phonon interaction of optical phonons in graphite. From the decay of the transient anti-Stokes scattering of the G-mode following ultrafast…

Materials Science · Physics 2015-05-14 Hugen Yan , Daohua Song

We point out that plasmons in doped graphene simultaneously enable low-losses and significant wave localization for frequencies below that of the optical phonon branch $\hbar\omega_{Oph}\approx 0.2$ eV. Large plasmon losses occur in the…

Mesoscale and Nanoscale Physics · Physics 2015-05-14 Marinko Jablan , Hrvoje Buljan , Marin Soljačić

We have investigated the effects of ozone treatment on graphene by Raman scattering. Sequential ozone short-exposure cycles resulted in increasing the $p$ doping levels as inferred from the blue shift of the 2$D$ and $G$ peak frequencies,…

Mesoscale and Nanoscale Physics · Physics 2015-05-19 F. Alzina , H. Tao , J. Moser , Y. Garcia , A. Bachtold , C. M. Sotomayor-Torres

Using a first-principles approach we calculate the acoustic electron-phonon couplings in graphene for the transverse (TA) and longitudinal (LA) acoustic phonons. Analytic forms of the coupling matrix elements valid in the long-wavelength…

Materials Science · Physics 2013-11-22 Kristen Kaasbjerg , Kristian S. Thygesen , Karsten W. Jacobsen

We investigate electron-phonon couplings, scattering rates, and mean free paths in zigzag-edge graphene strips with widths of the order of 10 nm. Our calculations for these graphene nanostrips show both the expected similarity with…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 D. Gunlycke , H. M. Lawler , C. T. White

Semiconductor materials are the foundation of modern electronics, and their functionality is dictated by the interactions between fundamental excitations occurring on (sub-)picosecond timescales. Using time-resolved Raman spectroscopy and…

One of the salient features of graphene is the very high carrier mobility that implies tremendous potential for use in electronic devices. Unfortunately, transport measurements find the expected high mobility only in freely suspended…

Mesoscale and Nanoscale Physics · Physics 2015-06-04 Søren Ulstrup , Marco Bianchi , Richard Hatch , Dandan Guan , Alessandro Baraldi , Dario Alfè , Liv Hornekær , Philip Hofmann

We calculate the phonons in a graphene nanoconstriction(GNC) in the presence of a high current density. The Joule-heating, current-induced forces, and coupling to electrode phonons is evaluated using first principles nonequilibrium DFT-NEGF…

Mesoscale and Nanoscale Physics · Physics 2014-03-18 Tue Gunst , Jing-Tao Lü , Per Hedegård , Mads Brandbyge

Using in-situ Raman scattering from phosphorene channel in an electrochemically top-gated field effect transistor, we show that its phonons with A$_g$ symmetry depend much more strongly on concentration of electrons than that of holes,…

We report a comprehensive micro-Raman scattering study of electrochemically-gated graphene field-effect transistors. The geometrical capacitance of the electrochemical top-gates is accurately determined from dual-gated Raman measurements,…

Mesoscale and Nanoscale Physics · Physics 2016-08-08 Guillaume Froehlicher , Stéphane Berciaud

Inelastic light scattering spectra of Bi_2Se_3 and Sb_2Te_3 single crystals have been measured over the temperature range from 5 K to 300 K. The temperature dependence of dominant A^{2}_{1g} phonons shows similar behavior in both materials.…

In recent years, phonon electron carrier dragging has emerged as an innovative approach for modulating energy transfer in low dimensional systems. In this Letter, we explore the fundamental mechanisms of electron-phonon coupling and the…

Mesoscale and Nanoscale Physics · Physics 2025-06-10 Houssem Rezgui

We study effects of strong impurities on the heat transfer in a coupled electron-phonon system in disordered graphene. A detailed analysis of the electron-phonon heat exchange assisted by such an impurity through the 'resonant…

Mesoscale and Nanoscale Physics · Physics 2018-02-14 K. S. Tikhonov , I. V. Gornyi , V. Yu. Kachorovskii , A. D. Mirlin

The temperature effect on the Raman scattering efficiency is investigated in $\varepsilon$-GaSe and $\gamma$-InSe crystals. We found that varying the temperature over a broad range from 5 K to 350 K permits to achieve both the resonant…

Reflectance and transmittance of graphene in the optical region are analyzed as a function of frequency, temperature, and carrier density. We show that the optical graphene properties are determined by the direct interband electron…

Mesoscale and Nanoscale Physics · Physics 2009-11-13 L. A. Falkovsky
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