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Related papers: Beyond Eliashberg superconductivity in MgB2: anhar…

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Based on results from femtosecond time-resolved photoemission, we compare three different methods for determination of the electron-phonon coupling constant {\lambda} in Eu and Ba-based 122 FeAs compounds. We find good agreement between all…

Superconductivity · Physics 2013-08-13 L. Rettig , R. Cortés , H. S. Jeevan , P. Gegenwart , T. Wolf , J. Fink , U. Bovensiepen

In this paper, through an exhaustive analysis within the Migdal-Eliashberg theory, we show the incompatibility of experimental data of Rb$_3$C$_{60}$ with the basic assumptions of the standard theory of superconductivity. For different…

Superconductivity · Physics 2009-11-07 E. Cappelluti , C. Grimaldi , L. Pietronero , S. Strässler , G. A. Ummarino

The paradigmatic Migdal-Eliashberg theory of the electron-phonon problem is central to the understanding of superconductivity in conventional metals. This powerful framework is justified by the smallness of the Debye frequency relative to…

Superconductivity · Physics 2020-06-19 Debanjan Chowdhury , Erez Berg

The electron-phonon coupling strength in the spin-split valence band maximum of single-layer MoS$_2$ is studied using angle-resolved photoemission spectroscopy and density functional theory-based calculations. Values of the electron-phonon…

Within a two-band, strong coupling model we analyze SIS-tunneling conductance, Raman scattering and optical conductivity measured on $MgB_2$ samples. We find that features observed in tunneling and Raman spectroscopy at intermediate…

Superconductivity · Physics 2007-05-23 C. P. Moca , B. Janko

We have investigated the effect of unconventional pairing mechanism in MgB2 using a two-band model within the framework of Bogoliubov-Valatin formalism. The approach incorporates the intra- band s-wave interaction in the s- and p-bands, as…

Superconductivity · Physics 2017-06-22 O. C. Abah , G. C. Asomba , C. M. I. Okoye

In this chapter we review the essentials of conventional electron-phonon superconductivity, as provided through the Migdal-Eliashberg formalism. Signatures of the electron-phonon interaction, as they appear in conventional superconductors,…

Superconductivity · Physics 2007-05-23 F. Marsiglio , J. P. Carbotte

Coupling between $\sigma$-bonding electrons and phonons is generally very strong. To metallize $\sigma$-electrons provides a promising route to hunt for new high-T$_c$ superconductors. Based on this picture and first-principles density…

Superconductivity · Physics 2020-03-03 Miao Gao , Xun-Wang Yan , Zhong-Yi Lu , Tao Xiang

We report an experimental and theoretical investigation of the electron-boson interaction in KFe2As2 by point-contact (PC) spectroscopy, model, and ab-initio LDA-based calculations for the standard electron-phonon Eliashberg function. The…

Characterization of the first ever laboratory produced metallic hydrogen sample relies on measurements of optical spectra. Here we present first-principles calculations of the reflectivity of hydrogen between 400 and 600 GPa in the…

Superconductivity · Physics 2018-02-07 Miguel Borinaga , Julen Ibañez-Azpiroz , Aitor Bergara , Ion Errea

The remarkable anharmonicity of the E_{2g} phonon in MgB_2 has been suggested in literature to play a primary role in its superconducting pairing. We investigate, by means of LDA calculations, the microscopic origin of such an anharmonicity…

Superconductivity · Physics 2009-11-07 Lilia Boeri , Giovanni B. Bachelet , Emmanuele Cappelluti , Luciano Pietronero

We report on study of the electronic anisotropy of the newly discovered MgB2 superconductor using the in-plane resistivity measurements in magnetic field applied perpendicular and parallel to Mg and B planes of MgB2 single crystals. The…

Superconductivity · Physics 2009-11-07 Yu. Eltsev , S. Lee , K. Nakao , N. Chikumoto , S. Tajima , N. Koshizuka , M. Murakami

We examine the different possible symmetries of the superconducting gap obtained by solving the Eliashberg equations. We consider an electron-phonon interaction in a strong coupling scenario. The Coulomb pseudopotential plays the crucial…

supr-con · Physics 2009-10-30 G. Santi , T. Jarlborg , M. Peter , M. Weger

Super-high resolution laser-based angle-resolved photoemission spectroscopy measurements have been carried out on a heavily overdoped (Bi,Pb)2Sr2CuO6 (Tc> 5 K) superconductor. Taking advantage of the high-precision data on the subtle change…

The mechanisms for strong electron-phonon coupling predicted for hydrogen-rich alloys with high superconducting critical temperature ($T_c$) are examined within the Migdal-Eliashberg theory. Analysis of the functional derivative of $T_c$…

Superconductivity · Physics 2017-09-28 K. Tanaka , J. S. Tse , H. Liu

We investigate the dynamics of a phonon-mediated superconductor driven out of equilibrium. The electronic hopping amplitude is ramped down in time, resulting in an increased electronic density of states. The dynamics of the coupled…

Superconductivity · Physics 2016-04-12 M. A. Sentef , A. F. Kemper , A. Georges , C. Kollath

We determined electronic relaxation times via pump-probe optical spectroscopy using sub-15 fs pulses for the normal state of two different cuprate superconductors.We show that the primary relaxation process is the electron-phonon…

By means of density functional theory the electronic structure of the MgB2 superconductor was characterised and compared with that of the related iso-structural systems: AlB2, ZrB2, NbB2, and TaB2. Using the full-potential linearized…

Superconductivity · Physics 2009-11-07 Pablo de la Mora , Miguel Castro , Gustavo Tavizon

The strong coupling Eliashberg theory plus vertex correction is used to calculate maps of transition temperature (Tc) in parameter-space characterizing superconductivity. Based on these Tc maps, crossover behaviors are found when…

Superconductivity · Physics 2010-03-31 W. Fan

First-principles studies of the electron-phonon coupling in graphene predict a high coupling strength for the $\sigma$ band with $\lambda$ values of up to 0.9. Near the top of the $\sigma$ band, $\lambda$ is found to be $\approx 0.7$. This…

Mesoscale and Nanoscale Physics · Physics 2017-02-28 Federico Mazzola , Thomas Frederiksen , Thiagarajan Balasubramanian , Philip Hofmann , Bo Hellsing , Justin W. Wells
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