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Related papers: Van Hove Singularity and Apparent Anisotropy in th…

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We report the electronic structures and transport properties of a chiral crystal NbGe$_2$, which is a candidate for a coupled electron-phonon liquid. The electrical resistivity and thermoelectric power of NbGe$_2$ exhibit clear differences…

Strongly Correlated Electrons · Physics 2023-11-21 Yoshiki J. Sato , Ai Nakamura , Rei Nishinakayama , Ryuji Okazaki , Hisatomo Harima , Dai Aoki

We investigate the role of electron-hole correlations in the absorption of freestanding monolayer and bilayer graphene using optical transmission spectroscopy from 1.5 to 5.5 eV. Line shape analysis demonstrates that the ultraviolet region…

Mesoscale and Nanoscale Physics · Physics 2015-05-20 Dong-Hun Chae , Tobias Utikal , Siegfried Weisenburger , Harald Giessen , Klaus. v. Klitzing , Markus Lippitz , Jurgen H. Smet

Graphene is an ideal platform to study many-body effects due to its semimetallic character and the possibility to dope it over a wide range. Here we study the width of graphene's occupied $\pi$-band as a function of doping using…

Strongly Correlated Electrons · Physics 2016-08-10 Søren Ulstrup , Malte Schüler , Marco Bianchi , Felix Fromm , Christian Raidel , Thomas Seyller , Tim Wehling , Philip Hofmann

Phosphorene, an emerging elemental two-dimensional (2D) direct band gap semiconductor with fascinating structural and electronic properties distinctively different from other 2D materials such as graphene and MoS2, is promising for novel…

Materials Science · Physics 2015-04-21 Yongqing Cai , Qingqing Ke , Gang Zhang , Yuan Ping Feng , Vivek B Shenoy , Yong-Wei Zhang

We study the strength of the electron-phonon interaction on Fe single adatoms on MgO/Ag(100) based on many-body \textit{ab-initio} spin collinear calculations. In particular, we analyze the relative importance of the substrate and, among…

Mesoscale and Nanoscale Physics · Physics 2021-11-19 Haritz Garai-Marin , Julen Ibañez-Azpiroz , Peio Garcia-Goiricelaya , Idoia G. Gurtubay , Asier Eiguren

Electron-phonon coupling directly determines the stability of cooperative order in solids, including superconductivity, charge and spin density waves. Therefore, the ability to enhance or reduce electron-phonon coupling by optical driving…

We investigate the Fano-type line shape of the Ba mode of Y_{1-x}Ca_xBa_2Cu_3O_{6+y} films observed in Raman spectra with A_1g symmetry. The line shape is described with an extended Fano formula that allows us to obtain the bare phonon…

Superconductivity · Physics 2015-06-25 A. Bock , S. Ostertun , K. -O. Subke

A computational method is developed whereby the reflectivity of low-energy electrons from a surface can be obtained from a first-principles solution of the electronic structure of the system. The method is applied to multilayer graphene.…

Mesoscale and Nanoscale Physics · Physics 2014-01-21 R. M. Feenstra , M. Widom

A flattened electronic band is one of several possible routes for increasing the strength of the pairing interactions in a superconductor. With this in mind, we show here that thermodynamic measurements of the high-Tc cuprates reveal an…

Strongly Correlated Electrons · Physics 2023-03-24 Neil Harrison , Mun K. Chan

We calculate the contribution of unscreened and screened scalar and vector potential electron acoustic phonon coupling to resistivity in disordered graphene through Keldysh Greens function method within the diffusive limit. We obtain…

Mesoscale and Nanoscale Physics · Physics 2020-09-17 M Obaidurrahman , S S Z Ashraf

The unique properties of graphene offer immense opportunities for applications to many scientific fields, as well as societal needs, beyond our present imagination. One of the important features of graphene is the relatively simple…

Materials Science · Physics 2018-04-27 Otakar Frank , Mildred S. Dresselhaus , Martin Kalbac

We employ the first-principles GW+Bethe Salpeter equation approach to study the electronic structure and optical absorption spectra of uniaxial strained graphene with many-electron effects included. Applied strain not only induces an…

Materials Science · Physics 2015-05-30 Yufeng Liang , Shouting Huang , Li Yang

The electronic structure of few-layer graphene (FLG) samples with crystalline order was investigated experimentally by infrared absorption spectroscopy for photon energies ranging from 0.2 - 1 eV. Distinct optical conductivity spectra were…

Materials Science · Physics 2015-05-18 Kin Fai Mak , Jie Shan , Tony F. Heinz

Graphene is a novel two-dimensional material with fascinating electrodynamic properties like the ability to support collective electron oscillations (plasmons) accompanied by tight confinement of electromagnetic fields. Our goal is to…

Mesoscale and Nanoscale Physics · Physics 2013-03-15 Marinko Jablan

On the basis of the Kubo formula we evaluated the optical conductivity of a graphene sheet. The full behavior of frequency as well as temperature dependence of the optical conductivity is presented. We show that the anisotropy of…

Mesoscale and Nanoscale Physics · Physics 2008-10-07 Chao Zhang , Lei Chen , Zhongshui Ma

In their work, Yan et al. [Phys. Rev. B 88, 121403 (2013)] employing density functional perturbation theory (DFPT) calculations, demonstrate that silicene and germanene show weaker Kohn anomalies in the $\Gamma$-$E_g$ and $K$-$A_1$ phonon…

Materials Science · Physics 2017-07-27 M. E. Cifuentes-Quintal , O. de la Peña-Seaman , R. de Coss

We suggest that the phonon dispersion in cuprates becomes strongly anisotropic due to interaction with spin waves; moreover the phonon dispersion becomes singular along $|k_x|=|k_y|$ directions. This would allow more electrons to form…

Superconductivity · Physics 2007-05-23 Daniel L. Miller

We study electron-electron and electron-phonon mediated pairing in the Holstein extended Hubbard model on the Kagome lattice near the van Hove fillings, and investigate their combined effects on electron pairing states. We find that their…

Strongly Correlated Electrons · Physics 2024-02-02 Xianxin Wu , Debmalya Chakraborty , Andreas P. Schnyder , Andrés Greco

The superconducting pairing of electrons in doped graphene due to in-plane and out-of-plane phonons is considered. It is shown that the structure of the order parameter in the valley space substantially affects conditions of the pairing.…

Mesoscale and Nanoscale Physics · Physics 2015-05-19 Yu. E. Lozovik , S. L. Ogarkov , A. A. Sokolik

We compute electron-phonon coupling (EPC) of selected phonon modes in graphene and graphite using various ab-initio methods. The inclusion of non-local exchange-correlation effects within the GW approach strongly renormalizes the square EPC…

Materials Science · Physics 2008-08-28 Michele Lazzeri , Claudio Attaccalite , Ludger Wirtz , Francesco Mauri