Thermal conductivity of two-dimensional BC₃: a comparative study with two-dimensional C₃N

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Single-layer boron-carbon nitride (SLBC) and carbon nitride (SLCN) are 2D materials with potential thermal applications.
• Understanding their thermal transport properties is crucial for designing advanced materials.

Purpose of the Study:

• To investigate and compare the thermal conductivities of SLBC and SLCN sheets.
• To analyze the effects of temperature, defects, and strain on their thermal transport.
• To explore the suitability of SLBC for thermal applications.

Main Methods:

• Molecular dynamics (MD) simulations were employed to study thermal conductivity.
• Calculations included vibrational density of states (VDOS) to understand phonon behavior.
• Simulations analyzed responses to temperature variations, vacancy defects, and uniaxial/biaxial strains.

Main Results:

• SLBC and SLCN exhibit isotropic thermal conductivity in the basal plane.
• Predicted thermal conductivities are 488.54 W m⁻¹ K⁻¹ for SLBC and 799.87 W m⁻¹ K⁻¹ for SLCN.
• SLBC shows lower thermal conductivity than SLCN due to stronger phonon-defect scattering and weaker bonding.
• Thermal conductivity decreases with increasing temperature and defect concentration.
• Strain effects vary: compressive strain is negative, tensile strain is initially positive then negative, with biaxial strain causing a more severe reduction.
• Tensile strain impacts thermal transport more significantly in SLBC than SLCN.

Conclusions:

• SLBC exhibits lower thermal conductivity than SLCN, influenced by phonon scattering and bonding stiffness.
• Temperature and defects reduce thermal conductivity, with varying degrees of impact on SLBC and SLCN.
• External strain significantly alters thermal transport, with tensile strain having a pronounced effect on SLBC.
• SLBC nanomembranes show promise for diverse thermal management applications.