Strong-coupling BCS superconductivity in noncentrosymmetric BaPtSi3: a low-temperature study

Area of Science:

• Condensed Matter Physics
• Materials Science
• Superconductivity

Background:

• Noncentrosymmetric superconductors are a unique class of materials exhibiting complex electronic properties.
• BaPtSi3 belongs to the BaNiSn3-type tetragonal structure, a family known for noncentrosymmetric superconductivity.
• Understanding the superconducting mechanism in these materials is crucial for advancing condensed matter physics.

Purpose of the Study:

• To investigate the superconducting properties of BaPtSi3, specifically the temperature dependence of its magnetic penetration depth.
• To determine the nature of the superconducting gap (isotropic or anisotropic) in BaPtSi3.
• To evaluate the applicability of the Bardeen-Cooper-Schrieffer (BCS) theory to BaPtSi3 superconductivity.

Main Methods:

• High-quality BaPtSi3 single crystals were synthesized.
• Magnetic penetration depth measurements were performed as a function of temperature.
• Experimental data was analyzed using the strong-coupling BCS model.

Main Results:

• A temperature-independent magnetic penetration depth was observed below approximately 0.2 Tc.
• This behavior provides strong evidence for an isotropic superconducting gap in BaPtSi3.
• Superfluid density across the entire temperature range is well-described by the BCS model with an isotropic gap (Δ0 ≈ 2kBTc).

Conclusions:

• BaPtSi3 exhibits conventional Bardeen-Cooper-Schrieffer superconductivity with an isotropic superconducting gap.
• The findings support the theoretical understanding of superconductivity in nonmagnetic, noncentrosymmetric materials with tetragonal structures.
• This study contributes to the broader understanding of unconventional superconductors and their potential applications.