Predicting diamond-like Co-based chalcogenides as unconventional high temperature superconductors

Area of Science:

• Condensed Matter Physics
• Materials Science
• Solid State Chemistry

Background:

• Unconventional high-temperature superconductivity (high-T_c) remains a key research area.
• 3d transition metal compounds with d⁷ filling configurations are potential candidates for high-T_c materials.
• Cobalt-based chalcogenides with vertex-shared CoAs₄ tetrahedra represent a novel material genome.

Purpose of the Study:

• To predict the potential for unconventional high-temperature superconductivity in Co-based chalcogenides.
• To investigate the magnetic ground states and electronic properties of these materials.
• To explore the effect of doping on superconductivity.

Main Methods:

• First-principles calculations of magnetic ground states.
• Analysis of electronic structures and magnetic interactions.
• Prediction of superconducting properties upon doping.

Main Results:

• Co-based chalcogenides exhibit a G-type antiferromagnetic insulating ground state.
• The antiferromagnetic interaction is strongest in Co-based compounds due to t_2g orbital participation.
• A sharp decrease in magnetism from Co- to Ni-based compounds is observed, similar to Fe- to Co-based pnictides.
• Doping is predicted to induce a strong d-wave pairing superconducting state.

Conclusions:

• Co-based chalcogenides with a diamond-like structure are promising for unconventional high-T_c.
• The observed magnetic quenching serves as an electronic signature for high-T_c potential.
• Doping is a viable strategy to achieve superconductivity in this material family.