Designing superhard magnetic material in clathrate \b{eta}-C3N2 through atom embeddedness

TL;DR

This study predicts that doping ta-C3N2 with H or F atoms creates superhard materials with controllable magnetic properties, combining mechanical strength and magnetism for potential spintronic applications.

Contribution

It introduces a novel approach to design multifunctional superhard magnetic materials by atom embeddedness in clathrate ta-C3N2 using density functional theory.

Findings

Hydrogen-doped ta-C3N2 is an antiferromagnetic semiconductor with a Vickers hardness of 49.0 GPa.

Fluorine-doped ta-C3N2 is a ferromagnetic semi-metal with a Vickers hardness of 48.2 GPa.

Both doped materials exhibit high mechanical hardness and tunable magnetic phases.

Abstract

Designing new compounds with the coexistence of diverse physical properties is of great significance for broad applications in multifunctional electronic devices. In this work, based on density functional theory, we predict the coexistence of mechanical superhardness and the controllable magnetism in the clathrate material \b{eta}-C3N2 through the implant of the external atom into the intrinsic cage structure. Taking hydrogen-doping (H@\b{eta}-C3N2) and fluorine-doping (F@\b{eta}-C3N2) as examples, our calculations indicate these two doped configurations are stable and discovered that they belong to antiferromagnetic semiconductor and ferromagnetic semi-metal, respectively. These intriguing magnetic phase transitions originate from their distinctive band structure around the Fermi level and can be well understood by the 3D Hubbard model with half-filling occupation and the Stoner model. Moreover, the high Vickers hardness of 49.0 GPa for H@\b{eta}-C3N2 and 48.2 GPa for F@\b{eta}-C3N2 are obtained, suggesting they are clathrate superhard materials as its host. Therefore, the incorporation of H and F in \b{eta}-C3N2 gives rise to a new type of superhard antiferromagnetic semiconductor and superhard ferromagnetic semimetal, respectively, which could have potential applications in harsh conditions. Our work provides an effective strategy to design a new class of highly desirable multifunctional materials with excellent mechanical properties and magnetic properties, which may arouse spintronic applications in superhard materials in the future.