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The superconducting gap of MgB2 has been studied by high-resolution angle-resolved photoemission spectroscopy (ARPES). The momentum(k)-resolving capability of ARPES enables us to identify the s- and p-orbital derived bands predicted from…

Superconductivity · Physics 2007-05-23 S. Tsuda , T. Yokoya , Y. Takano , H. Kito , A. Matsushita , F. Yin , H. Harima , S. Shin

We report first-principles calculations of the electronic band structure and lattice dynamics for the new superconductor MgB$_{2}$. The excellent agreement between theory and our inelastic neutron scattering measurements of the phonon…

The discovery of high-temperature superconductivity in iron pnictides raised the possibility of an unconventional superconducting mechanism in multiband materials. The observation of Fermi-surface(FS)-dependent nodeless superconducting gaps…

We present a comparison of electronic structure of MgB2 and TaB2, the two new superconductors, as well as VB2, calculated using full-potential, density- functional-based methods in P6/mmm crystal structure. Our results, described in terms…

Superconductivity · Physics 2007-05-23 Prabhakar P. Singh

We report self-consistent {\it ab initio} calculations of structural and electronic properties for the B- and Mg-terminated MgB$_{2}$ (0001) surfaces. We employ ultra-soft pseudopotentials and plane wave basis sets within the generalized…

Materials Science · Physics 2009-11-07 Zhenyu Li , Jinlong Yang , J. G. Hou , Qingshi Zhu

The nature and symmetry of the superconducting gap function in the noncentrosymmetric superconductor (NCS) Li2Pt3B, even many years after its discovery, appears to be full of contradictions. In this letter based on the existing band…

Superconductivity · Physics 2015-05-30 Soumya P. Mukherjee , Tetsuya Takimoto

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

The accurate charge density of MgB2 was observed at room temperature(R.T.) and 15K by the MEM(Maximum Entropy Method)/Rietveld analysis using synchrotron radiation powder data. The obtained charge density clearly revealed the covalent…

Materials Science · Physics 2009-11-07 E. Nishibori , M. Takata , M. Sakata , H. Tanaka , T. Muranaka , J. Akimitsu

To understand the superconductivity in MgB2, several two-band models of superconductivity were proposed. In this paper, by using the relativistic fermion model, we clearize the effect of the lower band in the superconductivity.

Superconductivity · Physics 2007-05-23 Tadafumi Ohsaku

Motivated by the recent results on impurity effects in MgB2, we present a theoretical model for a two-band superconductor in which the character of quasiparticle motion is ballistic in one band and diffusive in the other. We apply our model…

Superconductivity · Physics 2009-11-11 K. Tanaka , D. F. Agterberg , J. Kopu , M. Eschrig

We provide a comparison of accurate full potential band calculations of the Fermi surfaces areas and masses of MgB2 and ZrB2 with the de Haas-van Alphen date of Yelland et al. and Tanaka et al., respectively. The discrepancies in areas in…

Superconductivity · Physics 2009-11-07 H. Rosner , J. M. An , W. E. Pickett , S. -L. Drechsler

We have used angular resolved photoemission to measure the angular dependence of the superconducting gap in highly overdoped Bi2212 (Tc=65K). While the node at 45 degrees is conserved, we find substantial deviation from a first order d-wave…

The electronic band structures of the new superconducting (with T_c up to 7.7K) ternary silicides M(A_{0.5}Si_{0.5})_2 (M= Ca, Sr, Ba; A= Al, Ga) in the AlB_2-type structure have been investigated using the full-potential LMTO method. The…

Superconductivity · Physics 2009-11-07 I. R. Shein , N. I. Medvedeva , A. L. Ivanovskii

We have determined the structural properties of the superconducting compound MgB2 as a function of temperature from 11 K to 297 K and as a function of hydrostatic pressure up to 0.62 GPa using neutron powder diffraction. This compound, when…

Superconductivity · Physics 2009-11-07 J. D. Jorgensen , D. G. Hinks , S. Short

High-resolution laser-based angle-resolved photoemission measurements have been carried out on Bi$_2$Sr$_2$CaCu$_2$O$_{8+\delta}$ (Bi2212) and Bi$_2$Sr$_{2-x}$La$_x$CuO$_{6+\delta}$ (Bi2201) superconductors. Unexpected hybridization between…

Electronic Raman scattering studies on MgB2 single crystals as a function of excitation and polarization have revealed three distinct superconducting features: a clean gap below 37 cm-1 and two coherence peaks at 109 cm-1 and 78 cm-1 which…

Superconductivity · Physics 2007-10-16 G. Blumberg , A. Mialitsin , B. S. Dennis , N. D. Zhigadlo , J. Karpinski

Within the framework of non-stationary Ginzburg-Landau equations generalized on a case of two order parameters, we investigated dynamic characteristics of two-band superconducting MgB2 filaments in a voltage-driven regime. We calculated…

Superconductivity · Physics 2012-09-20 V. N. Fenchenko , Y. S. Yerin

We use angle resolved photoemission spectroscopy (ARPES) to study the band structure of BaFe2As2 and CaFe2As2, two of the parent compounds of the iron arsenic high temperature superconductors. We find clear evidence for band back folding…

We report a detailed study of the electronic and structural properties of the 39K superconductor \mgbtwo and of several related systems of the same family, namely \mgalbtwo, \bebtwo, \casitwo and \cabesi. Our calculations, which include…

Superconductivity · Physics 2009-11-07 G. Satta , G. Profeta , F. Bernardini , A. Continenza , S. Massidda

We investigate the electronic structure of a complex conventional superconductor, ZrB12 employing high resolution photoemission spectroscopy and ab initio band structure calculations. The experimental valence band spectra could be described…

Superconductivity · Physics 2013-12-03 S. Thakur , D. Biswas , N. Sahadev , P. K. Biswas , G. Balakrishnan , K. Maiti