# Large Thermoelectric Power Factor at Low Temperatures in One-Dimensional Telluride Ta4SiTe4

## TL;DR

This study discovers that one-dimensional telluride Ta4SiTe4 exhibits exceptionally high thermoelectric power factors at low temperatures, promising for cryogenic cooling applications due to its unique electronic structure.

## Contribution

It reports the first observation of large thermoelectric power factors in Ta4SiTe4, highlighting the role of one-dimensional Dirac semimetal characteristics in thermoelectric performance.

## Key findings

- Achieved a power factor of 80 microW cm-1 K-2 at 130 K
- Doping increased power factor to 170 microW cm-1 K-2 at 220-280 K
- Outperforms Bi2Te3-Sb2Te3 alloys at room temperature

## Abstract

We report the discovery of a very large thermoelectric power over -400 microV K-1 in the whisker crystals of a one-dimensional telluride Ta4SiTe4, while maintaining a low electrical resistivity of rho = 2 mohm cm, yielding a very large power factor of P = 80 microW cm-1 K-2 at an optimum temperature of 130 K. This temperature is widely controlled from the cryogenic temperature of 50 K to room temperature by chemical doping, resulting in the largest P of 170 microW cm-1 K-2 at 220-280 K. These P values far exceed those of the Bi2Te3-Sb2Te3 alloys at around room temperature, offering an avenue for realizing the practical-level thermoelectric cooling at low temperatures. The coexistence of a one-dimensional electronic structure and a very small band gap appearing in the vicinity of the Dirac semimetals probably causes the very large power factors in Ta4SiTe4, indicating that the "one-dimensional Dirac semimetal" is a promising way to find high-performance thermoelectric materials for the low temperature applications.

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Source: https://tomesphere.com/paper/1705.00404