Elastic stiffening induces one-dimensional phonons in thin Ta2Se3 nanowires

Compared to extensive studies of thermal transport in two-dimensional materials, very limited attention has been paid to the corresponding phenomenon in quasi-one-dimensional van der Waals crystals. Here, we show that Ta2Se3 can be easily exfoliated into thin nanowires, indicating strong anisotropy in the bonding strength within the basal plane. Systematic thermal property measurements disclose signatures of one-dimensional phonons as the nanowire hydraulic diameter reduces below 19.2 nm with linearly escalating thermal conductivity as temperature increases and size dependence inconsistent with the classical size effect. We further show that these unusual transport properties are induced by elastic stiffening occurring for wires of < 30 nm diameter. Published under an exclusive license by AIP Publishing.

Automated summary

Compared to two-dimensional materials, the thermal transport phenomenon in quasi-one-dimensional van der Waals crystals has been less studied. In this study, we demonstrate the strong anisotropy in bonding strength within the basal plane of Ta2Se3, which can be easily exfoliated into thin nanowires. Thermal property measurements reveal the presence of one-dimensional phonons when the nanowire hydraulic diameter decreases below 19.2 nm. The thermal conductivity linearly increases with temperature and shows a size dependence inconsistent with the classical size effect. These unusual transport properties are induced by elastic stiffening occurring for wires of < 30 nm diameter.