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Related papers: Nonadiabatic coupling effects in MgB$_2$ reexamine…

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Phonon-phonon anharmonic effects have a strong influence on the phonon spectrum; most prominent manifestation of these effects are the softening (shift in frequency) and broadening (change in FWHM) of the phonon modes at finite temperature.…

A method is proposed for the inclusion of electron correlation in the calculation of the temperature dependence of band structures arising from electron-phonon coupling. It relies on an efficient exploration of the vibrational phase space…

Materials Science · Physics 2016-03-04 Bartomeu Monserrat

We present a comparison of electron-phonon interaction in NbB_2 and MgB_2, calculated using full-potential, density-functional-based methods in P6/mmm crystal structure. Our results, described in terms of (i) electronic structure, (ii)…

Superconductivity · Physics 2009-11-07 Prabhakar P. Singh

The Raman spectrum of the superconductor MgB$_{2}$ has been measured as a function of the Tc of the film. A striking correlation is observed between the $T_{c}$ onset and the frequency of the $E_{2g}$ mode. Analysis of the data with the…

Superconductivity · Physics 2009-11-10 K. A. Yates , G. Burnell , N. A. Stelmashenko , D. -J. Kang , H. N. Lee , B. Oh , M. G. Blamire

We show how the coupling between the phonons and electrons in a strongly correlated metal can result in phonon frequencies which have a non-monotonic temperature dependence. Dynamical mean-field theory is used to study the Hubbard-Holstein…

Strongly Correlated Electrons · Physics 2009-10-31 J. Merino , Ross H. McKenzie

We report temperature dependence of low-energy phonons in magnetic nonsuperconducting TbNi2B2C single crystals measured by inelastic neutron scattering. We observed a low-temperature softening and broadening of two phonon branches,…

Superconductivity · Physics 2011-09-16 S. Anissimova , A. Kreyssig , O. Stockert , M. Loewenhaupt , D. Reznik

We introduce a simple, solvable model of double-barrier resonant tunneling structure which includes the effects of electron-electron and electron-phonon scattering. The model is based on a generalized effective-mass equation where a…

Condensed Matter · Physics 2007-05-23 Enrique Diez , Angel Sanchez , Francisco Dominguez-Adame

The photoluminescence spectra of band-edge transitions in GaN is studied as a function of temperature. The parameters that describe the temperature dependence red-shift of the band-edge transition energy and the broadening of emission line…

Materials Science · Physics 2009-11-11 Niladri Sarkar , Subhasis Ghosh

Whereas electron-phonon scattering typically relaxes the electron's momentum in metals, a perpetual exchange of momentum between phonons and electrons conserves total momentum and can lead to a coupled electron-phonon liquid with unique…

It is shown that the sharp peak in the $E_{2g}$ Raman spectrum of superconducting $MgB_2$ is due to a bound state caused by the electron-phonon coupling. Our theory explains why this peak appears only in the spectra with $E_{2g}$ symmetry…

Superconductivity · Physics 2009-11-10 R. Zeyher

We study the effects of Kohn anomalies on the superconducting properties in electron- and hole-doped cases of monolayer blue phosphorene, considering both adiabatic and non-adiabatic phonon dispersions using first-principles calculations.…

Superconductivity · Physics 2022-10-05 Mohammad Alidoosti , Davoud Nasr Esfahani , Reza Asgari

Theory of superconductivity in two-band non-adiabatic systems with strong electron correlations in the linear approximation over non-adiabaticity is built in the article. Having assumed weak electron-phonon interaction analytical…

Superconductivity · Physics 2007-05-23 M. E. Palistrant , V. A. Ursu

We have observed a strongly broadened Raman band of MgB2 that shows anomalously large pressure dependence of its frequency. This band and its pressure dependence can be interpreted as the E2g zone center phonon, which is strongly anharmonic…

We report the first Raman scattering measurements of BaC$_6$, SrC$_6$, and YbC$_6$, which along with new data on CaC$_6$, permits a systematic study of the phonons and the electron-phonon interaction within the doped graphene layers of…

Strongly Correlated Electrons · Physics 2010-06-08 Mark P. M. Dean , Christopher A. Howard , Siddharth S. Saxena , Mark Ellerby

In small Fermi energy metals, disorder can deeply modify superconducting state properties leading to a strong suppression of the critical temperature $T_c$. In this paper, we show that also normal state properties can be seriously…

Superconductivity · Physics 2009-11-07 E. Cappelluti , C. Grimaldi , L. Pietronero

The standard Eliashberg - McMillan theory of superconductivity is essentially based on the adiabatic approximation. Here we present some simple estimates of electron - phonon interaction within Eliashberg - McMillan approach in non -…

Superconductivity · Physics 2020-02-03 M. V. Sadovskii

The occurrence of non-adiabatic effects in the vibrational properties of metals have been predicted since the 60's, but hardly confirmed experimentally. We report the first fully \emph{ab initio} calculations of non-adiabatic frequencies of…

Materials Science · Physics 2009-11-13 A. Marco Saitta , Michele Lazzeri , Matteo Calandra , Francesco Mauri

We report $^{11}$B-NMR study on Al-doped MgB$_2$ that addresses a possible mechanism for a high superconducting (SC) transition temperature ($T_c$) of $\sim 40$ K in recently discovered MgB$_2$. The result of nuclear spin lattice relaxation…

Superconductivity · Physics 2009-11-07 H. Kotegawa , K. Ishida , Y. Kitaoka , T. Muranaka , N. Nakagawa , H. Takagiwa , J. Akimitsu

We study the role of non-adiabatic Holstein electron-phonon coupling on the neutral-ionic phase transition of charge transfer crystals which can be tuned from continuous to discontinuous, using exact numerical diagonalization. The variation…

Condensed Matter · Physics 2009-10-28 G. P. Borghi , A. Girlando , A. Painelli , J. Voit

A high order series expansion is employed to study the thermodynamical properties of a S=1/2 chain coupled to dispersionless phonons. The results are obtained without truncating the phonon subspace since the series expansion is performed…

Strongly Correlated Electrons · Physics 2007-05-23 Alexander Bühler , Götz S. Uhrig , Jaan Oitmaa