Gold Interlayer Promotes Superconductivity in Single and Double Atomic Pb Layers on Si(100)

Area of Science:

• Condensed Matter Physics
• Materials Science
• Surface Science

Background:

• Superconductivity in low-dimensional materials is highly sensitive to structural and electronic properties.
• Thin films of lead (Pb) on semiconductor substrates are of interest for superconductivity.
• Intermixing and Peierls transitions can degrade superconducting properties in 1D systems.

Purpose of the Study:

• To investigate the effect of an atomic gold (Au) interlayer on the structure and superconductivity of Pb films on Si(100).
• To explore methods for controlling low-dimensional superconductivity at the atomic scale.
• To mitigate degradation risks in ultrathin superconducting films.

Main Methods:

• Fabrication of single- and double-atom thick Pb films on Si(100) with an atomic Au interlayer.
• Characterization of Pb film structures, including Si(100)1 × 7-(Pb, Au) and Si(100)5 × 1-(Pb, Au) superstructures.
• Transport measurements to evaluate superconducting properties.

Main Results:

• The Au interlayer enabled the formation of stable, single- and double-atom thick Pb films with 2D square-lattice structures and 1D Pb adatom chains.
• These structures exhibited bundles of quasi-1D metallic bands.
• Pb films with the Au interlayer showed enhanced superconducting properties compared to those grown directly on Si(100).

Conclusions:

• The (Pb, Au)/Si(100) system effectively controls low-dimensional superconductivity at the atomic limit.
• The Au interlayer prevents intermixing with the substrate and suppresses the Peierls transition, preserving superconductivity.
• This approach offers a pathway to engineer advanced superconducting materials.