Basically, the conversion efficiency of a thermoelectric module grows with the ZT values of its constituting materials and with the temperature difference between the hot and cold side. For example, with a ZT value of 1, the best efficiency you could obtain in an ideal case for a hot side of 500°C and a cold side of 200°C would be around 8%. With a ZT value of 0.01, whatever the temperature difference you have, the conversion efficiency will be very very low. So I am afraid that the answer to your question is "no": with a low ZT of 0.01, the sample does not have good thermoelectric properties. For comparison, alloys like chromel or constantan (used for thermocouples) have ZT values around 0.1.

Noway! zT should be at least 0.5 for device application regardless of electrical conductivity value.

This value of ZT is very small. But, there may be practically very specific areas of practical use. For example, I mean the case if you need to have environmentally friendly or very cheap materials. In this case, there may be a place for the use of such materials (specific thermoelectric sensors or medical probes)

No. It is not true. Good thermoelectric material should have at operation temperature both high electrical conductivity (e.g. , about 1000 S/cm) and low thermal conductivity (e.g., about 1 W/(K x m)). Only high conductivity is not enough. Metals are of high electrical conductivity, but of high thermal conductivity as well due to Wiedemann-Franz law. Metal are good reference materials for thermoelectric measurements but not effective thermoelectric materials (high electrical conductivity and very low ZT).

Dear Djalila,

To complement the answer of Mikhail Nitkin, I highly recommend the reading of the two following references:

1/ C. B. Vining, Nature Materials vol. 8, 83 (2009).

2/ C. Wood, Reports on Progress in Physics vol. 51, p. 459 (1988).

Best wishes,

Henni