Kostrzewa Małgorzata, Szczęśniak Radosław, Kalaga Joanna K, Wrona Izabela A
Institute of Physics, Jan Długosz University in Częstochowa, Ave. Armii Krajowej 13/15, 42-200, Częstochowa, Poland.
Institute of Physics, Częstochowa University of Technology, Ave. Armii Krajowej 19, 42-200, Częstochowa, Poland.
Sci Rep. 2018 Aug 10;8(1):11957. doi: 10.1038/s41598-018-30391-z.
The HS and HS compounds are the two candidates for the low-temperature phase of compressed sulfur-hydrogen system. We have shown that the value of Coulomb pseudopotential (μ*) for HS ([T] = 36 K and p = 112 GPa) is anomalously high. The numerical results give the limitation from below to μ* that is equal to 0.402 (μ* = 0.589), if we consider the first order vertex corrections to the electron-phonon interaction). Presented data mean that the properties of superconducting phase in the HS compound can be understood within the classical framework of Eliashberg formalism only at the phenomenological level (μ* is the parameter of matching the theory to the experimental data). On the other hand, in the case of HS it is not necessary to take high value of Coulomb pseudopotential to reproduce the experimental critical temperature relatively well (μ* = 0.15). In our opinion, HS is mainly responsible for the observed superconductivity state in the sulfur-hydrogen system at low temperature.
HS及HS化合物是压缩硫 - 氢体系低温相的两个候选物。我们已经表明，HS的库仑赝势（μ*）值（[T]=36K且p = 112GPa）异常高。数值结果给出了μ的下限限制，若我们考虑电子 - 声子相互作用的一级顶点修正，则该下限等于0.402（μ = 0.589）。所呈现的数据意味着，仅在唯象层面上，HS化合物中超导相的性质可以在Eliashberg形式理论的经典框架内得到理解（μ是使理论与实验数据匹配的参数）。另一方面，对于HS而言，要较好地重现实验临界温度，并不需要取高的库仑赝势值（μ = 0.15）。我们认为，HS是硫 - 氢体系中低温下观测到的超导态的主要成因。
