The isotope effect in H$\rm_{3}$S superconductor

TL;DR

This paper investigates the isotope effect in H₃S superconductor, showing that classical Eliashberg theory explains the low isotope coefficient, while the high value may be due to electron density of states effects.

Contribution

The study demonstrates that the classical Eliashberg approach accurately reproduces the low isotope coefficient, highlighting the role of electron density of states in the anomalously high values.

Findings

Eliashberg theory explains the low isotope coefficient at high pressure.

High isotope coefficient may result from electron density of states renormalization.

Isotope coefficient varies significantly with pressure in H₃S superconductor.

Abstract

The experimental value of ${\rm H_{3}S}$ isotope coefficient decreases from $2.37$ to $0.31$ in the pressure range from $130$ GPa to $200$ GPa. We have shown that the value of $0.31$ is correctly reproduced in the framework of the classical Eliashberg approach. On the other hand, the anomalously large value of the isotope coefficient ($2.37$) may be associated with the strong renormalization of the normal state by the electron density of states.