INVESTIGATION OF THE SUPERCONDUCTING PHASE IN METALLIC HYDROGEN NEAR THE PRESSURE OF METALLIZATION

In this paper, the thermodynamic properties of the superconducting state in the metallic hydrogen under the pressure at 347 GPa have been determined. In the framework of the Eliashberg formalism, it has been shown that the characteristic thermodynamic parameters deviate from the predictions of the BCS theory. In particular, the ratio ΔC(TC)/CN(TC) decreases from 1.96 to 1.72 depending on the assumed value of the Coulomb pseudopotential (μ* ∈ 〈0.08, 0.15〉). On the other hand, the ratio [Formula: see text] increases from 0.150 to 0.158.

Eliashberg Theory of the Superconducting State of Marginal Fermi Liquids

The marginal Fermi liquid (MFL) which describes the anomalous normal state of the cuprates is extended to a d-wave superconductive state. A phenomenological collective excitation, P0(ω,T), is taken such that it gives rise to, after renormalization, the MFL behavior in the normal state. With the P0, the renormalized excitation spectrum and pairing function in superconductive state are calculated self-consistently within the Eliashberg formalism. In the superconductive state, the self-energy deviates from the normal state MFL ω/T-scaling and develops a new energy scale of ω0≈2Δ, where Δ is the pairing amplitude.

PENETRATION DEPTH CALCULATION IN THE FRAMEWORK OF THE TWO-BANDS ELIASHBERG MODEL IN MgB2

We investigate the temperature dependence of the penetration depth λ(T) in MgB2 in the framework of the two-bands model using the Eliashberg formalism. We also study the influence of the impurities lifetime on the temperature dependence of λ(T). By direct comparison of the experimental data with theoretical results, a practical method to determine the orientation of the crystal is proposed.