Lower thermal conductivity of body centered cubic carbon (C14): a comparative study with diamond

In recent years, the material preparation technology has ushered into a stage of rapid development, increasingly more carbon materials are found to display superior properties, making them suitable for designing nano-scale devices. Within the applications of electronic devices, a considerable amount of consumed energy has to be converted into heat; thus the efficiency of heat transport inside these devices can largely determine their overall performance. Decent elucidations of the heat transport mechanisms within low-dimensional materials will be helpful to achieve thermal management control of the related devices and furthermore, to improve their conversion efficiency. It is well understood that the heat transport within these kinds of materials is largely associated with their structural features. In this study, we focused on a novel material, body centered cubic carbon (C14), which is composed of sp³ hybridized carbon atoms. Such a novel material displays superior electronic properties; however, its thermal properties remain to be investigated. In order to systematically evaluate the practical applicability of this novel material, first-principles calculations were employed to systematically solve its structure; furthermore, its thermal conductivity, phonon dispersion spectrum, phonon properties, Grüneisen parameters, scattering phase space and mechanical properties were all described in detail. We found that C14 performs well in heat transport; and via systematical comparison with another allotrope, diamond, its transport mechanism was further summarized. We hope the physical insights provided by this study could serve as theoretical support for nano-scale device design.