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Related papers: Electron-Phonon Spectral Density of MgB2 from Opti…

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The search of the phonon structure at the above-gap energies was carried out for $d^{2}V/dI^{2}(V)$ spectra of MgB$_{2}$ point contacts with a normal metal. The two-band model is assumed not only for the gap structure in…

Superconductivity · Physics 2009-11-07 I. K. Yanson , V. V. Fisun , N. L. Bobrov , Yu. G. Naidyuk , W. N. Kang , Eun-Mi Choi , Hyun-Jung Kim , Sung-Ik Lee

We present electronic structure calculations together with resistivity, susceptibility, and specific heat measurements for TaB$_2$ to search for the recently contradictorily reported superconductivity and to study related normal state…

Superconductivity · Physics 2009-11-07 H. Rosner , W. E. Pickett , S. -L. Drechsler , A. Handstein , G. Behr , G. Fuchs , K. Nenkov , K. -H. Müller , H. Eschrig

We investigated optical absorption spectra near the fundamental absorption edge of beta-FeSi2 single crystals by transmission measurements. The phonon structure corresponding to the emission and absorption component was clearly observed in…

Materials Science · Physics 2009-11-10 Haruhiko Udono , Isao Kikuma , Tsuyoshi Okuno , Yasuaki Masumoto , Hiroyuki Tajima

We investigate the electronic background as well as the O2-O3 mode at 330 cm^-1 of highly doped YbBa2Cu3O7-delta in B1g symmetry. Above the critical temperature Tc the spectra consist of an almost constant electronic background and…

Superconductivity · Physics 2007-05-23 S. Ostertun , J. Kiltz , T. Wolf , A. Bock

A complete set of all optical phonon modes predicted by symmetry for bixbyite structure indium oxide is reported here from a combination of far-infrared and infrared spectroscopic ellipsometry, as well as first principle calculations.…

Raman spectra of the MgB2 ceramic samples were measured as a function of pressure up to 32 GPa at room temperature. The spectrum at normal conditions contains a very broad peak at ~590 cm-1 related to the E2g phonon mode. The frequency of…

Materials Science · Physics 2009-11-07 K. P. Meletov , J. Arvanitidis , M. P. Kulakov , N. N. Kolesnikov , G. A. Kourouklis

We present a first principles investigation of the lattice dynamics and electron-phonon coupling of the superconductor MgB_2 and the isostructural AlB_2 within the framework of density functional perturbation theory using a mixed-basis…

Superconductivity · Physics 2009-11-07 K. -P. Bohnen , R. Heid , B. Renker

Two-phonon contributions to meV-resolved inelastic x-ray scattering spectra of MgB2 at 300K are identified, in good agreement, in both intensity and energy, with a harmonic calculation using the force constant matrix from ab-inito LDA…

Superconductivity · Physics 2007-05-23 A. Q. R. Baron , H. Uchiyama , R. Heid , K. -P. Bohnen , Y. Tanaka , S. Tsutsui , D. Ishikawa , S. Lee , S. Tajima

We propose phonon spectroscopy by electric measurements of the low-temperature conductance of coupled-quantum dots, specifically employing dephasing of the quantum electronic transport by the phonons. The setup we consider consists of a…

Mesoscale and Nanoscale Physics · Physics 2013-05-29 A. Ueda , O. Entin-Wohlman , M. Eto , A. Aharony

The "standard" theory of a normal metal consists of an effective electron band which interacts with phonons and impurities. The effects due to the electron-phonon interaction are often delineated within the Migdal approximation; the…

Strongly Correlated Electrons · Physics 2009-11-10 Fatih Dogan , Frank Marsiglio

We present a first-principles study of the temperature- and density-dependent intrinsic electrical resistivity of graphene. We use density-functional theory and density-functional perturbation theory together with very accurate Wannier…

We report an inelastic neutron scattering investigation of phonons with energies up to 159 meV in the conventional superconductor YNi$_2$B$_2$C. Using the SWEEP mode, a newly developed time-of-flight technique involving the continuous…

We address the effect of band filling on the effective electron mass $m^*$ and the superconducting critical temperature $T_c$ in a electron-phonon system. We compare the vertex corrected theory with the non-crossing approximation of the…

Superconductivity · Physics 2009-11-10 E. Cappelluti , S. Ciuchi , C. Grimaldi , L. Pietronero

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

Lortz et al. [Phys. Rev. B 73, 024512 (2006)] have utilized specific heat and resistivity measurements as "thermal spectroscopies" to deconvolve the spectrum of the electron-phonon interaction in YB$_6$ assuming a major role of the low…

Superconductivity · Physics 2013-04-01 P. Szabo , J. Girovsky , Z. Pribulova , J. Kacmarcik , T. Mori , P. Samuely

State-of-the-art model Hamiltonians, like Fr\"ohlich's, or density functional theory approaches to electron-phonon interaction suffer from a severe overscreening error. This is due to the incorrect treatment of the screening of the ionic…

Materials Science · Physics 2023-11-17 Fulvio Paleari , Andrea Marini

We report on the inelastic-scattering rate of electrons on phonons and relaxation of electron energy studied by means of magnetoconductance, and photoresponse, respectively, in a series of strongly disordered superconducting NbN films. The…

We consider an electron-phonon system in two and three dimensions on square, hexagonal and cubic lattices. The model is a modification of the standard Holstein model where the optical branch is appropriately curved in order to have a…

Statistical Mechanics · Physics 2009-10-31 N. Macris , C. -A. Piguet

Observed optical reflectivity in the infrared spectral region is compared with theoretical predictions in a strongly coupled electron-phonon system. Starting from a Froehlich Hamiltonian, the spectral functions and their temperature…

Superconductivity · Physics 2007-05-23 H. J. Kaufmann , E. G. Maksimov , E. K. H. Salje

Using a computationally inexpensive frozen phonon approach we have developed a technique which can be used to screen large unit cell materials and systems for enhanced superconducting critical temperatures. The method requires only density…

Superconductivity · Physics 2024-05-07 Oliver A. Dicks , Kateryna Foyevtsova , Ilya Elfimov , Rohit Prasankumar , George Sawatzky