High Thermoelectric Performance in Two-Dimensional Tellurium: An Ab Initio Study.

In 2016, bulk tellurium was experimentally observed as a remarkable thermoelectric material. Recently, two-dimensional (2D) tellurium, called tellurene, has been synthesized and has exhibited unexpected electronic properties compared with the 2D MoS2. They have also been fabricated into air-stable and highly efficient field-effect transistors. There are two stable 2D tellurene phases. One (β-Te) has been confirmed with an ultralow lattice thermal conductivity (κL). However, the study of the transport properties of the other more stable phase, α-Te, is still lacking. Here, we report the thermoelectric performance and phonon properties of α-Te using Boltzmann transport theory and first-principles calculations. A maximum ZT value of 0.83 is achieved under a reasonable hole concentration, suggesting that the monolayer α-Te is a potential competitor in the thermoelectric field.