Geometric contribution to the measurement of thermoelectric power and Nernst coefficient in a strong magnetic field

TL;DR

This study investigates how sample shape affects measurements of thermoelectric power and Nernst coefficient in strong magnetic fields, revealing geometric contributions that influence the results.

Contribution

It demonstrates that sample shape significantly impacts thermoelectric measurements, highlighting the importance of geometric factors in such experiments.

Findings

Fat-Bridge shape yields about 10% smaller Nernst coefficient.

Thermoelectric power is reduced by 1-10% in the Fat-Bridge shape.

Geometric effects contribute to measurement variations.

Abstract

On the measurement of thermoelectric power and Nernst coefficient, we used two kinds of shapes for a sample. One is "Bridge shape" and the other is, we call,"Fat-Bridge shape". The latter has 5 times wider main body than the former. We used pure n-InSb in this experiment, whose carrier condensation measured at 77K was $6.6 \times 10^{-14} cm^{-3}.$ The length of sample is 17mm and temperature difference induced between the edges in that direction were about $10^{\circ}$C or $100^{\circ}$C near a room temperature range of 0 to $100^{\circ}$C. Magnetic induction applied in the perpendicular direction to temperature gradient was in the range of 0 up to 4 Tesla. In the case of "Fat-Bridge shape", we detected about 10% smaller Nernst coefficient and 1 to 10% smaller thermoelectric power comparing to the "Bridge shape". We suppose this phenomena is due to the geometric contribution on the different shape of samples.