Direct evidence for a multiple superconducting gap in MgB2 from high-resolution photoemission spectroscopy

Abstract

We study the new binary intermetallic superconductor MgB2 using high-resolution photo-emission spectroscopy. The superconducting-state spectrum measured at 5.4 K shows a coherent peak with a shoulder structure, in sharp contrast to that expected from a simple isotropic-gap opening. The spectrum can be well reproduced using the weighted sum of two Dynes functions with the gap sizes of 1.7 and 5.6 meV. Temperature-dependent study shows that both gaps close at the bulk transition temperature. These results provide spectroscopic evidence for a multiple gap of MgB2.

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References in corpus (20)

• Superconductivity of metallic boron in MgB_2
• Beyond Eliashberg superconductivity in MgB2: anharmonicity, two-phonon scattering, and multiple gaps
• Boron Isotope Effect in Superconducting MgB${}_2$
• Electron-phonon interaction in the normal and superconducting states of MgB2
• Phonon dispersion and electron-phonon coupling in MgB_2 and AlB_2
• Superconducting Properties of MgB2 Bulk Materials Prepared by High Pressure Sintering
• Evidence for Two Superconducting Gaps in $Mg{B}_2$
• Scanning Tunneling Spectroscopy in MgB2
• Tunneling spectroscopy in small grains of superconducting MgB2
• Evidence for Strong-coupling S-wave Superconductivity in MgB2 :11B NMR Study
• Nature of bonding and electronic structure in MgB2, a boron intercalation superconductor
• High-Resolution Photoemission Study of MgB2
• Hole Superconductivity in $Mg{B}_2$: a high $T_c$ cuprate without Cu
• Penetration Depth Measurements in MgB_2: Evidence for Unconventional Superconductivity
• Lower Critical Field at Odds with A S-Wave Superconductivity in The New Superconductor $Mg{B}_2$
• Electron-Phonon or Hole Superconductivity in $Mg{B}_2$?
• Penetration Depth and Anisotropy in MgB2
• Two-Band-Type Superconducting Instability in MgB2
• Superconductivity Driven by the Interband Coulomb Interaction and Implications for the Superconducting Mechanism of MgB2
• Optical measurements of the superconducting gap in MgB2

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• Reversible magnetization measurement of the anisotropy of the London penetration depth in MgB2 single crystals
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• Tunnel junctions on as-grown superconducting MgB2 thin films
• Superconducting Properties of Combustion Synthesized MgB2
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• Leggett Modes in Dirac Semimetals
• Anisotropic superconductivity in La(O,F)BiSeS crystals revealed by field-angle dependent Andreev reflection spectroscopy
• Heat capacity of mesoscopically disordered superconductors:implications to MgB${}_2$
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• Correlations of superconducting fluctuations in a two-gap system
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• Accurate Electron-phonon Interactions from Advanced Density Functional Theory
• Finite Temperature Phase Diagrams of a Two-band Model of Superconductivity
• Pressure Effects and Large Polarons in Layered MgB_2 Superconductor
• Transition Spectra for a BCS Superconductor with Multiple Gaps: Model Calculations for MgB_2
• Superconducting energy gaps, low temperature specific heat, and quasiparticle spectra of MgB2
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• Shrinking of fluctuation region in a two-band superconductor
• Properties and challenges of hot-phonon physics in metals: MgB${}_2$ and other compounds
• Enhancing long-range order in disordered two-band s-wave superconductors
• Three-Body Collective Excitations in the Superconducting Phase of $Mg{B}_2$