21-25 July 2019
Connecticut Convention Center, Level 6
US/Eastern timezone

M2Po2A-03 [27]: The issue of induction the superconducting state in selected compressed sulfur and hydrogen systems

23 Jul 2019, 13:30
2h
Level 6, Cryo Expo Exhibit Hall ()

Level 6, Cryo Expo Exhibit Hall

Speaker

Ms Małgorzata Kostrzewa (Institute of Physics, Jan Długosz University in Częstochowa)

Description

Thermodynamic properties of superconducting state in the $\rm H_{5}S_{2}$ system were analyzed precisely. The calculations were carried out in two cases: included the lowest-order vertex correction-scheme VCEE (Vertex Corrected Eliashberg Equations), on the other hand we get the model without the vertex corrections, the so-called CEE scheme (Classical Eliashberg Equations). It has been proven that under pressure 112 GPa , the superconducting state induced in the $\rm H_{5}S_{2}$ compound is characterized by anomalously high value of Coulomb pseudopotential (also after taking into account the vertex corrections to the electron-phonon interaction). The analysis contains also the parameters study of superconducting state, that is induced in the $\rm{H_{4}S_{3}}$ and ${\rm H_{2}S}$ compounds. The superconducting state of $\rm{H_{4}S_{3}}$ compound is the BCS type, however it cannot be equated with the experimentally measured low-temperature superconducting state in the compressed hydrogen sulfide, since it has a very low critical temperature. On the other hand, has been shown that the superconducting state in ${\rm H_{2}S}$ compound has thermodynamic parameters with values close to the values determined for $\rm H_{5}S_{2}$ in the CEE (Classical Eliashberg Equations) scheme and is not the state of BCS type. In our opinion, experimentally was observed the superconducting state in the ${\rm H_{2}S}$ compound, which is kinetically protected in the samples prepared at the low temperature. It should be emphasized that in the case of ${\rm H_{2}S}$ reproducing the experimental dependence of critical temperature on the pressure does not require anomalously high value of Coulomb pseudopotential.

Primary authors

Ms Małgorzata Kostrzewa (Institute of Physics, Jan Długosz University in Częstochowa) Prof. Radosław Szczęśniak (Institute of Physics, Częstochowa University of Technology)

Presentation Materials