Anomalously high value of Coulomb pseudopotential for the H5S2 superconductor

作者：Kostrzewa Malgorzata^*; Szczesniak Radoslaw; Kalaga Joanna K; Wrona Izabela A

来源：Scientific Reports, 2018, 8(1): 11957.

DOI：10.1038/s41598-018-30391-z

The H5S2 and H2S compounds are the two candidates for the low-temperature phase of compressed sulfur-hydrogen system. We have shown that the value of Coulomb pseudopotential (mu*) for H5S2 ([T-C](exp) = 36 K and p = 112 GPa) is anomalously high. The numerical results give the limitation from below to mu* that is equal to 0.402 (mu* = 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 H5S2 compound can be understood within the classical framework of Eliashberg formalism only at the phenomenological level (mu* is the parameter of matching the theory to the experimental data). On the other hand, in the case of H2S it is not necessary to take high value of Coulomb pseudopotential to reproduce the experimental critical temperature relatively well (mu* = 0.15). In our opinion, H2S is mainly responsible for the observed superconductivity state in the sulfur-hydrogen system at low temperature.

• 出版日期2018-8-10