Eur. Phys. J. B (2015) 88: 342
https://doi.org/10.1140/epjb/e2015-60752-6

Regular Article

Detailed study of the superconducting properties in compressed germane

Institute of Physics, Częstochowa University of Technology, Ave. Armii Krajowej 19, 42-200 Częstochowa, Poland

^a e-mail: adurajski@wip.pcz.pl

Received: 18 September 2015
Received in final form: 28 October 2015
Published online: 21 December 2015

Abstract

Hydrogen-rich compounds under extreme pressure are the most promising systems for searching a high-temperature superconductivity. In presented paper, we report analysis of the thermodynamic properties of hydrogenated germanium (germane, GeH₄) at 220 GPa obtained within the framework of the Migdal-Eliashberg theory. We observe that together with the increase of Coulomb pseudopotential from 0.1 to 0.3 the critical temperature decreases from 92.36 K to 52.80 K. A similar trend is also well-visible in the case of other thermodynamic properties. Moreover, we study the influence of external pressure on the superconducting state of GeH₄. On this basis we conclude that increase of pressure from 20 to 220 GPa has a pronounced effect on the thermodynamic stability of germane. Finally, it is proved that the properties of the superconducting state of GeH₄ differ markedly from predictions of the Bardeen-Cooper-Schrieffer (BCS) theory.