Atomically Resolved Defects on Thin Molybdenum Carbide (α-Mo₂C) Crystals

Area of Science:

• Materials Science
• Solid State Physics
• Surface Science

Background:

• Thin transition metal carbides (TMCs) show promise due to excellent mechanical, electrical, and stability properties.
• Understanding defect impacts on TMCs is vital for their application potential.
• Molybdenum carbide (α-Mo₂C) is a representative TMC with limited defect characterization.

Purpose of the Study:

• To investigate the atomic-scale nature of defects in thin molybdenum carbide (α-Mo₂C) crystals.
• To correlate defect types with their effects on electrical conductivity.
• To elucidate the role of defects in the physical properties of α-Mo₂C.

Main Methods:

• Growth of thin α-Mo₂C crystals using chemical vapor deposition (CVD).
• Atomic-resolution characterization via conductive atomic force microscopy (C-AFM) under ambient conditions.
• Computational analysis using *ab initio* density functional theory (DFT) calculations.

Main Results:

• Defects were identified and classified by their impact on conductivity (enhancement/attenuation) and spatial distribution (compact/extended).
• C-AFM revealed variations in conductivity landscape attributed to specific defect types.
• DFT calculations provided insights into the atomic structure and electronic nature of observed defects.

Conclusions:

• Defect characterization in α-Mo₂C is essential for understanding its electronic properties.
• The combined C-AFM and DFT approach effectively probes defect-property relationships in TMCs.
• This study provides a foundation for defect engineering in molybdenum carbide for tailored applications.