Mode-selected electron-phonon coupling in superconducting Pb nanofilms determined from He atom scattering

Area of Science:

• Condensed Matter Physics
• Materials Science
• Surface Science

Background:

• Electron-phonon coupling (EPC) is crucial for superconductivity.
• Measuring mode-selected EPC strengths in thin films is experimentally challenging.

Purpose of the Study:

• To develop and demonstrate a novel method for measuring mode-selected EPC strengths in superconducting films.
• To utilize inelastic helium atom scattering (IHAS) for probing phonon modes within ultrathin lead films.

Main Methods:

• Utilized inelastic helium atom scattering (IHAS) on superconducting lead (Pb) films.
• Leveraged the extended range of EPC in ultrathin films to detect surface and near-surface phonons.
• Established a direct proportionality between IHAS scattering amplitudes and EPC strengths for individual phonon modes.

Main Results:

• Successfully measured the EPC strength for each phonon mode in Pb films.
• Demonstrated that IHAS can detect phonons even 1 nm below the film surface.
• IHAS scattering amplitudes are proportional to mode-specific EPC strengths.

Conclusions:

• Inelastic helium atom scattering (IHAS) is a powerful new tool for mode-lambda spectroscopy.
• This technique provides unprecedented insight into electron-phonon interactions in thin film superconductors.
• The findings open new avenues for understanding and engineering superconducting properties.