Th₂Mo₂Ir₂Si₄C: An Intergrown Superconductor by Structure Design.

Area of Science:

• Materials Science
• Condensed Matter Physics
• Solid State Chemistry

Background:

• Discovering new superconductors in complex multicomponent systems is challenging.
• Superconductors with distinct, separate superconducting layers are exceptionally rare in complex materials.

Purpose of the Study:

• To design and synthesize a novel quinary intermetallic compound with distinct superconducting layers.
• To investigate the structural and superconducting properties of the newly synthesized material.

Main Methods:

• Utilized a block-layer model and formation energy calculations for material design.
• Synthesized the quinary intermetallic compound Th2Mo2Ir2Si4C.
• Characterized the material's structure and superconducting properties using electrical resistivity, magnetic susceptibility, and specific heat measurements.

Main Results:

• Successfully synthesized Th2Mo2Ir2Si4C, which crystallizes in an intergrowth structure with alternating ThMo2Si2C and ThIr2Si2 block layers.
• Observed enhanced superconductivity with a transition temperature (Tc) of 3.4 K and a zero-temperature upper critical field (Hc2(0)) of 9.5 kOe.
• Identified Si-Ir bonding as the dominant interblock-layer interaction, leading to stronger coupling between layers.

Conclusions:

• The block-layer design strategy is effective for creating complex superconductors with distinct superconducting layers.
• The developed strategy can be applied to design other intergrowth systems incorporating various functional motifs.
• Th2Mo2Ir2Si4C represents a rare example of a complex superconductor with distinct superconducting layers, offering a new platform for superconductivity research.