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We characterize the superconducting state of phase pure polycrystalline samples of the new layered superconductor MgB$_2$ by specific heat measurements in magnetic fields up to 9 T. The characteristic jump at the superconducting transition…

Superconductivity · Physics 2007-05-23 R. K. Kremer , B. J. Gibson , K. Ahn

Graphene moire superlattices are outstanding platforms to study correlated electron physics and superconductivity with exceptional tunability. However, robust superconductivity has been measured only in magic-angle twisted bilayer graphene…

Mesoscale and Nanoscale Physics · Physics 2021-10-20 Young Woo Choi , Hyoung Joon Choi

Layered 1$T$-TiSe$_{2}$ has attracted much interest for the competition of charge density wave (CDW) and superconductivity in its bulk and even monolayer forms. Here we perform first-principles calculations of the electronic structure,…

Superconductivity · Physics 2018-08-01 Bao-Tian Wang , Peng-Fei Liu , Jing-Jing Zheng , Wen Yin , Fangwei Wang

We have examined theoretically the electronic band structure and Fermi surface of tetragonal low-temperature superconductor Bi2Pd. Our main results are that (i) the Pd 4d and Bi 6p states determine the main peculiarities of the…

Superconductivity · Physics 2012-08-09 I. R. Shein , A. L. Ivanovskii

The electronic structure of Na2Ti2Sb2O, a parent compound of the newly discovered titanium-based oxypnictide superconductors, is studied by photon energy and polarization dependent angle-resolved photoemission spectroscopy (ARPES). The…

Superconductivity · Physics 2015-05-11 S. Y. Tan , J. Jiang , Z. R. Ye , X. H. Niu , Y. Song , C. L. Zhang , P. C. Dai , B. P. Xie , X. C. Lai , D. L. Feng

The intermetallic compound TlBi$_2$ crystallizes in the MgB$_2$ structure and becomes superconducting below 6.2 K. Considering that both Tl and Bi have heavy atomic masses, it is puzzling why TlBi$_2$ is a conventional phonon-mediated…

Superconductivity · Physics 2023-12-27 Aiqin Yang , Xiangru Tao , Yundi Quan , Peng Zhang

We present the structural, electronic and superconducting properties of Li2B2 under pressure within the framework of the density functional theory. The structural parameters, electronic band structure, phonon frequency of the E2g phonon…

Superconductivity · Physics 2014-01-08 Edgar Martínez-Guerra , Filiberto Ortíz-Chi , Stefano Curtarolo , Romeo de Coss

The effect of electron correlation (EC) on the electronic structure in MgB$_2$, AlB$_2$ and ZrB$_2$, is studied by examining the partial density of states (PDOS) of B-2$p\sigma$ and $p\pi$ orbitals using the polarization dependence of x-ray…

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

The anomalous features of the Raman spectroscopy measurement in MgB$_2$ represent a still unresolved puzzle. In particular highly debated are the origin of the huge $E_{2g}$ phonon linewidth, the nature of the low energy ($\omega <…

Superconductivity · Physics 2009-11-11 E. Cappelluti

Heat capacity measurements of the delta-phase stabilized alloy Pu-Al suggest that strong electron-phonon coupling is required to explain the moderate renormalization of the electronic density of states near the Fermi energy. We calculate…

Materials Science · Physics 2011-04-08 M. J. Graf , T. Lookman , J. M. Wills , D. C. Wallace , J. C. Lashley

Taking as a starting point the results of LDA calculations, which show that in MgB2 the phonons have a strong quartic anharmonicity and that the bond-stretching electron-phonon interaction (EPI) has both a linear and a large quadratic…

Superconductivity · Physics 2009-11-10 M. Acquarone , L. Romano'

We present results of all-electron electronic structure calculations for the recently discovered d electron heavy fermion compound LiV_2O_4. The augmented spherical wave calculations are based on density functional theory within the local…

Strongly Correlated Electrons · Physics 2009-10-31 V. Eyert , K. -H. Hoeck , S. Horn , A. Loidl , P. S. Riseborough

The strength of the electron-phonon coupling parameter and its evolution throughout a solid's phase diagram often determines phenomena such as superconductivity, charge- and spin-density waves. Its experimental determination relies on the…

Using ab-initio calculations, we study the electronic structure of gallium-doped germanium, which was found recently to be a superconductor, with a critical temperature of 0.5 Kelvins, and a particularly low density of Cooper pairs. The…

Materials Science · Physics 2015-05-13 S. Lebegue

YPtBi, a topological semimetal with very low carrier density, was recently found to be superconducting below $T_\mathrm{c} = 0.77$\,K. In the conventional theory, the nearly vanishing density of states around the Fermi level would imply a…

Superconductivity · Physics 2016-04-06 Markus Meinert

We report first-principles calculations on the normal and superconducting state of CaBe(x)Si(2-x) (x=1), in the framework of density functional theory for superconductors (SCDFT). CaBeSi is isostructural and isoelectronic to MgB2 and this…

Superconductivity · Physics 2013-05-29 C. Bersier , A. Floris , A. Sanna , G. Profeta , A. Continenza , E. K. U. Gross , S. Massidda

We report first-principles calculations of the k- and T-dependent superconducting gap Delta(k,T) in MgB2 and its manifestation in various measured quantities. Because the Fermi surface has disconnected sheets with different electron-phonon…

Superconductivity · Physics 2007-05-23 Hyoung Joon Choi , David Roundy , Hong Sun , Marvin L. Cohen , Steven G. Louie

We have studied the lattice dynamics, electron-phonon coupling, and superconducting properties of $\alpha$-MoB$_2$, as a function of applied pressure, within the framework of density functional perturbation theory using a mixed-basis…

Superconductivity · Physics 2023-10-31 Marco-Antonio Carmona-Galván , Rolf Heid , Omar De la Peña-Seaman

It is argued that the origin of the buckling of the CuO$_{2}$ planes in certain cuprates as well as the strong electron-phonon coupling of the $B_{1g}$ phonon is due to the electric field across the planes induced by atoms with different…