arXiv subjects

B. J. Gibson

Publications and source records attributed to B. J. Gibson.

2 recordsLinked to original sources

arXiv2002

Specific heat of MgB$_2$ in a one- and a two-band model from first-principles calculations

The heat capacity anomaly at the transition to superconductivity of the layered superconductor MgB$_2$ is compared to first-principles calculations with the Coulomb repulsion, $μ^\ast$, as the only parameter which is fixed to give the measured $T_c$. We solve the Eliashberg equations for both an isotropic one-band and a two-band model with different superconducting gaps on the $π$ and $σ$ Fermi surfaces. The agreement with experiments is considerably better for the two-band model than for the one-band model.

cond-mat.supr-con↗

arXiv2001

Heat Capacity of MgB_2: Evidence for Moderately Strong Coupling Behavior

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 is observed and compared with the predictions of weak coupling BCS-theory and the $α$-model. Our analysis shows excellent agreement with the predictions for 2$Δ/k_BT_{\rm C}$ = 4.2(2) with a Sommerfeld term $γ_{\rm exp}$ of 3.1(1) mJ/mol K$^2$ indicating that MgB$_2$ is a superconductor in the moderately strong electron-phonon coupling regime.

cond-mat.supr-con↗