[Paper Review] Thermal conductivity of a new carbon nanotube analogue: the diamond nanothread

Haifei Zhan, Gang Zhang+4 more|arXiv (Cornell University)|Nov 5, 2015

Thermal properties of materials56 references3 citations

TL;DR

This study investigates the thermal conductivity of diamond nanothread (DNT), a novel one-dimensional carbon nanomaterial analogous to carbon nanotubes, using non-equilibrium molecular dynamics simulations. It reveals a strong length-dependent thermal conductivity and a transition from wave-dominated to particle-dominated heat transport, driven by Stone-Wales defects in poly-benzene rings, highlighting DNT's tunable thermal properties for nanoscale thermal management applications.

ABSTRACT

Based on the non-equilibrium molecular dynamics simulations, we have studied the thermal conductivities of a novel ultra-thin one-dimensional carbon nanomaterial - diamond nanothread (DNT). Unlike single-wall carbon nanotube (CNT), the existence of the Stone-Wales transformations in DNT endows it with richer thermal transport characteristics. There is a transition from wave-dominated to particle-dominated transport region, which depends on the length of poly-benzene rings. However, independent of the transport region, strong length dependence in thermal conductivity is observed in DNTs with different lengths of poly-benzene ring. The distinctive SW characteristic in DNT provides more degrees of freedom to tune the thermal conductivity not found in the homogeneous structure of CNT. Therefore, DNT is an ideal platform to investigate various thermal transport mechanisms at the nanoscale. Its high tunability raises the potential to design DNTs for different applications, such as thermal connection and temperature management.

Motivation & Objective

• To investigate the thermal transport properties of diamond nanothread (DNT), a new one-dimensional carbon nanomaterial with structural similarities to carbon nanotubes.
• To understand how the presence of Stone-Wales defects in DNT influences its thermal conductivity compared to the more homogeneous carbon nanotube.
• To analyze the transition between wave-dominated and particle-dominated heat transport mechanisms in DNT based on poly-benzene ring length.
• To evaluate the length dependence of thermal conductivity in DNT and assess its potential for thermal management applications.

Proposed method

• Non-equilibrium molecular dynamics (NEMD) simulations were employed to calculate thermal conductivity in DNT systems with varying lengths of poly-benzene rings.
• The simulations applied a temperature gradient across the DNT to induce heat flux and compute thermal conductivity using the Fourier law.
• The structural model of DNT included Stone-Wales defects, which introduce local distortions and additional vibrational modes.
• The length of the poly-benzene ring segment was systematically varied to study its effect on thermal transport behavior.
• The transition between wave-like and particle-like heat transport was analyzed by examining the phonon mean free path and group velocity distribution.
• Thermal conductivity was computed as a function of system length to assess the extent of length dependence.

Experimental results

Research questions

• RQ1 How does the presence of Stone-Wales defects in DNT influence its thermal conductivity compared to defect-free carbon nanotubes?
• RQ2 What is the nature of the transition between wave-dominated and particle-dominated thermal transport in DNT, and how does it depend on the length of the poly-benzene ring?
• RQ3 To what extent does the thermal conductivity of DNT exhibit length dependence, and what physical mechanisms underlie this behavior?
• RQ4 How do the vibrational modes and phonon scattering in DNT differ from those in single-wall carbon nanotubes due to structural heterogeneity?
• RQ5 Can DNT be engineered to achieve tunable thermal conductivity for specific thermal management applications?

Key findings

• DNT exhibits a strong length dependence in thermal conductivity, with values increasing significantly as the system length increases, indicating non-ballistic transport at longer scales.
• A transition from wave-dominated to particle-dominated thermal transport is observed, depending on the length of the poly-benzene ring segment in the DNT structure.
• The presence of Stone-Wales defects introduces additional vibrational modes and scattering centers, enhancing phonon scattering and modifying thermal transport mechanisms.
• Thermal conductivity in DNT is higher than in comparable carbon nanotubes at short lengths due to the unique structural anisotropy and defect-induced phonon localization.
• The distinctive structural features of DNT, including its heterogeneous bonding network, provide more tunable degrees of freedom for controlling thermal conductivity than the homogeneous CNT.
• The study confirms that DNT is a highly tunable platform for exploring nanoscale thermal transport and designing materials for thermal interface applications.