Abstract：
Thermal properties of nanomaterials have attracted much attention recently. Their thermal conductivity can become either very high or very low, depending on their structures and materials. The former case is expected to be useful in heat release in electronic devices, while the latter may have good thermoelectric properties. Carbon nanomaterials include both cases, and so are particularly interesting. In the present lecture, I will discuss the following two topics in the thermal and thermoelectric properties of carbon nanomaterials, with showing our simulation results.
(1) Thermal properties of carbon nanotubes: Carbon nanotubes have high thermal conductivity. They show interesting features such as the quantization of thermal conductance [1] and universal fluctuations in phonon transmission in isotope- disordered tubes [2].
(2) Thermoelectric properties of conical carbon nanofibers: On the contrary to nanotubes, conical carbon nanofibers have much lower thermal conductivities [3]. Owing to this, they can have excellent thermoelectric properties: according to our simulations, their figure of merit (ZT) can be much higher than 1 [3, 4].

References
[1] T. Yamamoto, et al., Phys. Rev. Lett. 92, 075502 (2004)
[2] T. Yamamoto, et al., Phys. Rev. Lett. 106, 215503 (2011).
[3] D.A. Thomas, et al., Trans. Mat. Res. Soc. Jpn. 38, 183 (2013).
[4] D.A. Thomas, et al., in preparation.

CV-Watanabe.pdf