Superconductivity in ternary chalcogenides Bi(2)Ni(3)X(2) (X = S, Se)

Area of Science:

• Condensed Matter Physics
• Materials Science
• Superconductivity Research

Background:

• Parkerite and related compounds Bi(2)Ni(3)X(2) (X = S, Se) are novel materials with potential superconducting properties.
• Understanding their physical characteristics is crucial for advancing superconductor technology.

Purpose of the Study:

• To investigate the physical properties of parkerite and Bi(2)Ni(3)X(2) compounds.
• To determine their superconducting behavior and classify them within existing theoretical frameworks.

Main Methods:

• Electrical resistivity measurements up to 400 K.
• Low-temperature resistivity and specific heat measurements.
• Analysis of superconducting transition temperature and upper critical fields.

Main Results:

• Both compounds display typical metallic electrical resistivity up to 400 K.
• Superconducting transitions were observed at approximately 0.7 K for both Bi(2)Ni(3)S(2) and Bi(2)Ni(3)Se(2).
• Upper critical fields at 0 K were determined as 95 mT for Bi(2)Ni(3)S(2) and 75 mT for Bi(2)Ni(3)Se(2).

Conclusions:

• The studied compounds are confirmed superconductors with weak-coupling BCS characteristics.
• Normal state properties include electronic specific heat coefficients (γ) of 11.4 mJ/mol·K² (Bi(2)Ni(3)S(2)) and 12.2 mJ/mol·K² (Bi(2)Ni(3)Se(2)).
• Debye temperatures (Θ(D)) were found to be 189 K for Bi(2)Ni(3)S(2) and 173 K for Bi(2)Ni(3)Se(2).