Single-Layer Clathrane: A Potential Superconducting Two-Dimensional Hydrogenated Metal Borocarbide

Area of Science:

• Materials Science
• Condensed Matter Physics
• Solid State Chemistry

Background:

• Three-dimensional (3D) metal borocarbide clathrates (MM'B6C6) serve as precursors.
• Stabilizing two-dimensional (2D) forms of these materials is challenging.

Purpose of the Study:

• To propose and investigate a new family of 2D metal borocarbide clathrane superconductors.
• To explore methods for stabilizing these 2D materials and tuning their superconducting properties.

Main Methods:

• First-principles calculations were employed to model and analyze the material properties.
• Investigated the effects of hydrogen passivation and surface metal decoration for stabilization.
• Analyzed the influence of hole concentration, structural anisotropy, and electron-phonon coupling on superconductivity.
• Studied the impact of biaxial strain on superconducting critical temperature (Tc).

Main Results:

• Successfully stabilized M2M'B8C8H8 monolayers through hydrogen passivation and metal decoration.
• Demonstrated tunable superconductivity in these 2D clathranes, dependent on doping and structure.
• Identified in-plane anisotropy as a factor limiting Tc.
• Showed that biaxial strain can mitigate anisotropy and significantly enhance Tc, with an average increase of 15.5 K.
• Predicted a substantial Tc increase for Sr3B8C8H8 from 11.3 K to 22.2 K under strain.

Conclusions:

• 2D metal borocarbide clathranes are identified as promising new superconductors.
• Superconductivity in these materials is tunable via strain engineering.
• These findings provide design principles for optimizing low-dimensional superconducting materials.