Cooper-pair distribution function [Formula: see text] for superconducting [Formula: see text] and [Formula: see...

Area of Science:

• Condensed Matter Physics
• Materials Science
• Quantum Mechanics

Background:

• The Cooper-pair distribution function is a theoretical tool to understand superconductor states.
• It provides insights into the spectral regions of Cooper pair formation.
• This function is derived from the Eliashberg spectral function and phonon density of states.

Purpose of the Study:

• To report the Cooper-pair distribution function for compressed hydrogen sulfide and lanthanum hydride superconductors.
• To investigate the influence of stable sulfur isotopes on this function in H3S.
• To correlate the Cooper-pair distribution function with the critical temperature and superconducting properties.

Main Methods:

• First-principles calculations of Eliashberg spectral functions.
• Determination of phonon density of states.
• Calculation and analysis of the Cooper-pair distribution function ([Formula: see text]).

Main Results:

• The Cooper-pair distribution function indicates Cooper pair formation in the 10-70 meV vibration energy range for these superconductors.
• Low-energy vibrations significantly influence electron-phonon superconductivity.
• Isotopic substitution of sulfur in H3S demonstrably alters the Cooper-pair distribution function and critical temperature.
• A direct proportionality was observed between the [Formula: see text] parameter and critical temperature ([Formula: see text]) values.

Conclusions:

• The low-energy region plays a crucial role in electron-phonon superconductivity.
• The Cooper-pair distribution function is a valuable tool for predicting and understanding superconducting properties.
• Isotopic effects provide further evidence for the importance of lattice vibrations in superconductivity.