Observation of the Crossover from Two-Gap to Single-Gap Superconductivity through Specific Heat Measurements in Neutron Irradiated MgB2

Abstract

We report specific heat measurements in neutron irradiated MgB2 samples, for which the critical temperature has been suppressed down to 8.5 K, but the superconducting transition remains extremely sharp, indicative of a defect structure extremely homogeneous. Our results demonstrate that the two-gap feature is evident in the temperature range above 21 K, while the single-gap superconductivity is well established as a bulk property not associated to local disorder fluctuations when Tc is decreased down to 11 K.

arXiv comment11 pages, 4 figures

References in corpus (21)

• Beyond Eliashberg superconductivity in MgB2: anharmonicity, two-phonon scattering, and multiple gaps
• Evidence for two superconducting energy gaps in MgB2 by point-contact spectroscopy
• Specific Heat of Mg ^{11}B_2
• Two Gap State Density in MgB${}_2$: A True Bulk Property or A Proximity Effect?
• First-Principles Calculation of the Superconducting Transition in MgB2 within the Anisotropic Eliashberg Formalism
• Phenomenological two-gap model for the specific heat of MgB_2
• Effect of magnetic and non-magnetic impurities on highly anisotropic superconductivity
• Band filling and interband scattering effects in MgB${}_2$: C vs Al doping
• Carbon doping of superconducting magnesium diboride
• Al substitution in MgB2 crystals: influence on superconducting and structural properties
• Neutron Irradiation of Mg11B2 : From the Enhancement to the Suppression of Superconducting Properties
• Toward one-band superconductivity in MgB2
• Thermodynamics of Two - Band Superconductors: The Case of MgB${}_2$
• Critical Field of Al-Doped MgB2 Samples: Correlation with the Suppression of Sigma-Band Gap
• Evidence for Single-gap Superconductivity in Mg(B_{1-x}C_x)_2 Single Crystals with x=0.132 from Point-Contact Spectroscopy
• Carbon-substitution dependent multiple superconducting gap of MgB${}_2$: a "sub-meV" resolution photoemission study
• Specific heat of MgB_2 after irradiation
• Systematic study of the two band/two gap superconductivity in carbon-substituted MgB2 by point-contact spectroscopy
• Retention of Two-Band Superconductivity in Highly Carbon-Doped MgB2
• Effect of damage by 2-MeV He ions on the normal and superconducting properties of magnesium diboride
• Two band/two gap superconductivity in carbon-substituted MgB2 evidenced by point-contact spectroscopy

Cited by in corpus (29)

• Probing multiband superconductivity by point-contact spectroscopy
• A review of two-band superconductivity: materials and effects on the thermodynamic and reversible mixed-state properties
• Doping evolution of superconducting gaps and electronic densities of states in Ba(Fe1-xCox)2As2 iron pnictides
• Effects of neutron irradiation on polycrystalline Mg11B2
• Bulk evidence of anisotropic $s$-wave pairing with no sign change in the kagome superconductor CsV${}_3$Sb${}_5$
• Fully gapped superconductivity with no sign change in the prototypical heavy-fermion CeCu2Si2
• Full-gap superconductivity robust against disorder in heavy-fermion CeCu2Si2
• Physical Property Characterization of Bulk MgB2 Superconductor
• Systematic study of disorder induced by neutron irradiation in MgB2 thin films
• Point-contact spectroscopy in neutron-irradiated Mg^{11}B_2
• Intraband versus interband scattering rate effects in neutron irradiated MgB2
• Multiband and impurity effects in infrared and optical spectra of MgB2
• Role of charge doping and lattice distortions in codoped Mg_{1-x}(AlLi)_{x}B_2 compounds
• Two-band parallel conductivity at terahertz frequencies in the superconducting state of MgB${}_2$.
• Neutron Irradiation of Sm-1111
• Disorder effects and current percolation in FeAs based superconductors
• Multi-band $s_{++}$ superconductivity in ${\text{V}}_3\text{Si}$ determined from the response to a controlled disorder
• Role of interband scattering in neutron irradiated MgB${}_2$ thin films by Scanning Tunneling Spectroscopy measurements
• Local Tunneling Study of Three-Dimensional Order Parameter in the $\pi$-band of Al-doped MgB${}_2$ Single Crystals
• Modification of intergrain connectivity, upper critical field anisotropy, and critical current density in ion irradiated MgB2 films
• Resistive transition in disordered superconductors with varying intergrain coupling
• Depinning frequency in a heavily neutron-irradiated MgB2 sample
• Effect of $\alpha$-particle irradiation on a NdFeAs(O,F) thin film
• Effect of disorder on the NMR relaxation rate in two-band superconductors
• Application prospects of MgB${}_2$ in view of its basic properties
• Microwave surface resistance of pristine and neutron-irradiated MgB2 samples in magnetic field
• Band filling and disorder effects on the normal state thermoelectric behavior in MgB2
• Fluxon dynamics in Li-Al codoped MgB2 by microwave surface resistance measurements
• Superconducting Symmetry Phases and Dominant bands in (Ca-) Intercalated AA- Bilayer Graphene