Thermoelectric Characteristics of A Single-Crystalline Topological Insulator Bi2Se3 Nanowire

The discovery of topological insulators (TIs) has motivated detailed studies on their physical properties, especially on their novel surface states via strong spin-orbit interactions. However, surface-state-related thermoelectric properties are rarely reported, likely because of the involvement of their bulk-dominating contribution. In this work, we report thermoelectric studies on a TI bismuth selenide (Bi2Se3) nanowire (NW) that exhibit a larger surface/volume ratio. Uniform single-crystalline TI Bi2Se3 NWs were successfully synthesized using a stress-induced growth method. To achieve the study of the thermoelectric properties of a nanowire (NW), including electrical conductivity (sigma), Seebeck coefficient (S), and thermal conductivity (kappa), a special platform for simultaneously performing all measurements on a single wire was designed. The properties of sigma, S, and kappa of a 200 nm NW that was well precharacterized using transmission electron microscope (TEM) measurements were determined using the four-probe method, the two-probe EMF across backward difference T measurement, and the 3 omega technique, respectively. The integrated TE properties represented by the figure of merit ZT (S-2 sigma T/kappa) were found to be in good agreement with a theoretical study of Bi2Se3 NW.

Automated summary

This study reports on the thermoelectric properties of topological insulator bismuth selenide nanowires, achieved using a specially designed platform for simultaneous measurements on a single wire. Experimental results on the properties of conductivity, Seebeck coefficient, and thermal conductivity were found to be in good agreement with theoretical studies.