# Hole-Doped M4SiTe4 (M = Ta, Nb) as an Efficient p-Type Thermoelectric Material for Low-Temperature Applications

## TL;DR

This study demonstrates the synthesis of high-performance p-type M4SiTe4 thermoelectric materials doped with Ti, showing promising efficiency for low-temperature cooling applications when combined with n-type counterparts.

## Contribution

It reports the successful creation of p-type M4SiTe4 with high thermoelectric performance, enabling low-temperature thermoelectric cooling devices.

## Key findings

- p-type M4SiTe4 reaches a power factor of ~60 μW cm-1 K-2 at 210 K
- A finite temperature drop was achieved in a device using p- and n-type M4SiTe4
- M4SiTe4 shows potential for practical low-temperature thermoelectric cooling

## Abstract

Solid-state thermoelectric cooling is expected to be widely used in various cryogenic applications such as local cooling of superconducting devices. At present, however, thermoelectric cooling using p- and n-type Bi2Te3-based materials has been put to practical use only at room temperature. Recently, M4SiTe4 (M = Ta, Nb) has been found to show excellent n-type thermoelectric properties down to 50 K. This paper reports on the synthesis of high-performance p-type M4SiTe4 by Ti doping, which can be combined with n-type M4SiTe4 in a cooling device at low temperatures. The thermoelectric power factor of p-type M4SiTe4 reaches a maximum value of approximately 60 uW cm-1 K-2 at 210 K and exceeds the practical level in a wide temperature range of 130-270 K. A finite temperature drop by Peltier cooling was also achieved in a cooling device made of p- and n-type Ta4SiTe4 whisker crystals. These results clearly indicate that M4SiTe4 is promising to realize a practical thermoelectric cooler for use at low temperatures, which are not covered by Bi2Te3-based materials.

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Source: https://tomesphere.com/paper/1907.10254