AA Stacking Phase of Diamane-like Carbon Nitrides - A First Principle Study and Its Thermal Conductivity

At a Glance

Metadata	Details
Publication Date	2025-03-19
Journal	ACS Omega
Authors	Teerachote Pakornchote, Sakarn Khamkaeo, Annop Ektarawong, Thiti Bovornratanaraks
Institutions	Thailand Center of Excellence in Physics, Chulalongkorn University
Analysis	Full AI Review Included

Technical Documentation & Analysis: AA Stacking Phase of Diamane-like Carbon Nitrides

This document analyzes the research concerning the thermal properties of AA-NCCN, a diamane-like carbon nitride, and connects the findings to 6CCVD’s expertise in high-performance MPCVD diamond materials.

Executive Summary

This first-principles study validates the exceptional thermal transport capabilities inherent to the diamond lattice structure, even in its two-dimensional (2D) variants.

Material Focus: Investigation of AA-NCCN, a novel AA-stacked, diamane-like 2D carbon nitride, benchmarked against AB-NCCN and H-diamane.
Key Achievement: AA-NCCN exhibits a high thermal conductivity (κ) of 1626 W/m-K at 300 K, a value comparable to that of bulk diamond.
Mechanism: The superior thermal performance is attributed to the AA-stacking configuration, which enhances the relaxation time of the ZA (out-of-plane acoustic) phonon mode, the dominant contributor to thermal transport in this material.
Methodology: Thermal properties were calculated using Density Functional Theory (DFT) combined with the Boltzmann Transport Equation (BTE) under the Relaxation Time Approximation (RTA).
Phase Coexistence: The small energy difference (6 meV/atom) between AA-NCCN and AB-NCCN suggests that these two phases could potentially coexist in synthesized 2D carbon nitride films.
6CCVD Relevance: This research reinforces the critical role of the diamond lattice structure in ultra-high thermal management applications, directly supporting the value proposition of 6CCVD’s Single Crystal (SCD) and Polycrystalline (PCD) diamond products.

Technical Specifications

The following hard data points were extracted from the computational results, primarily focusing on thermal conductivity and structural parameters.

Parameter	Value	Unit	Context
Thermal Conductivity (AA-NCCN)	1626	W/m-K	At 300 K (Room Temperature)
Thermal Conductivity (AB-NCCN)	1539	W/m-K	At 300 K
Thermal Conductivity (AA-NCCN)	256	W/m-K	At 1000 K
Thermal Conductivity (AB-NCCN)	239	W/m-K	At 1000 K
Energy Difference (AA vs AB)	6	meV/atom	AB-NCCN is the lower energy phase
In-Plane Lattice Parameter (AA-NCCN)	2.368	Å	Structural dimension
In-Plane Lattice Parameter (AB-NCCN)	2.392	Å	Structural dimension
Plane-Wave Energy Cutoff	800	eV	DFT Calculation Parameter
Convergence Criteria (Energy/Force)	10^-8	eV	DFT Calculation Parameter
Atomic Displacement (2^nd order IFCs)	0.01	Å	ALAMODE Input for IFC extraction
Atomic Displacement (3^rd order IFCs)	0.04	Å	ALAMODE Input for IFC extraction

Key Methodologies

The thermal properties of AA-NCCN and AB-NCCN were evaluated using advanced ab initio computational techniques:

Density Functional Theory (DFT): Calculations were performed using the Vienna ab initio Simulation Package (VASP), employing the generalized gradient approximation (GGA) and the Project Augmented Wave (PAW) method.
Ionic Relaxation: A Monkhorst-Pack k-point density of 11 × 11 × 1 was used for Brillouin zone integration, with a high plane-wave energy cutoff of 800 eV.
Interatomic Force Constants (IFCs): Second- and third-order IFCs were calculated using 4 × 4 × 1 supercells. IFC extraction utilized linear regression implemented in ALAMODE software.
Thermal Transport Calculation: The thermal conductivity (κ) was computed by solving the Boltzmann Transport Equation (BTE) using the Relaxation Time Approximation (RTA) method.
Convergence Parameters: A high q-point density of 200 × 200 × 1 was selected to ensure the convergence of thermal conductivity, relaxation time, heat capacity, and group velocity calculations.

6CCVD Solutions & Capabilities

The research highlights the pursuit of materials with thermal conductivity comparable to or exceeding that of bulk diamond. 6CCVD provides the foundational MPCVD diamond materials necessary for both benchmarking and advancing this field of 2D diamond-like structures.

Applicable Materials

To replicate or extend research into high-performance diamond-based thermal management, 6CCVD recommends the following materials:

6CCVD Material	Application Relevance to Research	Key Specifications
Optical Grade SCD	Thermal Benchmark & Substrate: Provides the highest intrinsic thermal conductivity (> 2000 W/m-K) against which novel 2D materials like AA-NCCN are compared. Ideal substrate for epitaxial growth or functionalization studies.	SCD thickness: 0.1 µm - 500 µm. Polishing: Ra < 1 nm (Ultra-smooth surface for 2D deposition).
High-Quality PCD	Large-Area Substrates: Suitable for large-scale synthesis of 2D carbon nitrides or diamane variants where large area (up to 125 mm) is critical for industrial scaling.	Plates/wafers up to 125 mm diameter. Polishing: Ra < 5 nm (Inch-size PCD).
Boron-Doped Diamond (BDD)	Doping Studies: The paper mentions nitrogen and boron substitution stabilizes the diamond-like form. BDD allows researchers to precisely control doping levels to investigate the impact of B-substitution on thermal and electronic properties.	Custom doping levels available. Thickness: 0.1 µm - 500 µm.

Customization Potential

The synthesis of 2D materials like diamane often requires highly specific substrate preparation and integration features. 6CCVD offers comprehensive customization services to meet these demands:

Custom Dimensions and Substrates: We provide SCD and PCD plates in custom dimensions, including large-area PCD wafers up to 125 mm, and thick substrates up to 10 mm for high-power applications.
Precision Thickness Control: For studies involving ultrathin films or 2D material precursors (like bilayer graphene), 6CCVD can supply diamond layers with thickness precisely controlled from 0.1 µm to 500 µm.
Advanced Metalization: The integration of 2D materials into devices requires robust electrical contacts. 6CCVD offers internal metalization capabilities, including Ti, Pt, Au, Pd, W, and Cu, allowing researchers to define custom electrode patterns directly onto the diamond substrate for thermal or electronic testing.
Surface Engineering: Achieving the ultra-smooth surfaces necessary for high-quality 2D material deposition is critical. Our polishing services ensure SCD surfaces meet Ra < 1 nm specifications.

Engineering Support

6CCVD’s in-house PhD engineering team specializes in the material science of CVD diamond and its applications in extreme environments. We can assist researchers and engineers with:

Material Selection: Guidance on selecting the optimal diamond grade (SCD vs. PCD, doping level, orientation) for 2D Diamane Synthesis and High Thermal Management projects.
Design Consultation: Support for defining custom dimensions, metalization schemes, and surface preparation requirements for novel device architectures.
Global Logistics: Reliable global shipping (DDU default, DDP available) ensures materials reach your lab efficiently.

For custom specifications or material consultation, visit 6ccvd.com or contact our engineering team directly.

View Original Abstract

Diamond-derived two-dimensional (2D) materials or diamanes show promising properties such as high elastic constants and giant thermal conductivity. We here present a new phase of diamane variants, AA-NCCN, which is a diamane-like structure of two carbon nitride layers in AA-stacking. Its thermal conductivity is higher than that of AB-NCCN, which is an AB-stacking configuration of NCCN, and hydrogenated diamane, computed by the relaxation time approximation (RTA) method. Because the RTA underestimates the thermal conductivity of some 2D materials, we propose that AA-NCCN could be a candidate whose thermal conductivity rivals that of diamond and a coexisting phase with AB-NCCN.

Tech Support

Original Source

DOI: https://doi.org/10.1021/acsomega.4c11181