title: Remarkable reduction of thermal conductivity in silicon nanotubes.
abstract: We propose to reduce the thermal conductivity of silicon nanowires (SiNWs) by introducing a small hole at the center, i.e., construct a silicon nanotube (SiNT) structure. Our numerical results demonstrate that a very small hole (only 1% reduction in cross section area) can induce a 35% reduction in room temperature thermal conductivity. Moreover, with the same cross section area, thermal conductivity of SiNT is only about 33% of that of SiNW at room temperature. The spatial distribution of vibrational energy reveals that localization modes are concentrated on the inner and outer surfaces of SiNTs. The enhanced surface-to-volume ratio in SiNTs reduces the percentage of delocalized modes, which is believed to be responsible for the reduction of thermal conductivity. Our study suggests SiNT is a promising thermoelectric material with low thermal conductivity.
authors.affiliation: Department of Physics and Centre for Computational Science and Engineering, National University of Singapore, Singapore 117546, Singapore.
authors.forename: Jie
authors.initials: J
authors.lastname: Chen
authors.forename: Gang
authors.initials: G
authors.lastname: Zhang
authors.forename: Baowen
authors.initials: B
authors.lastname: Li