  First principle calculations are performed to investigate the effect of polar
order strength on the thermoelectric (TE) properties of GeTe alloy in its
rhombohedral structure. The variation in the polarization state using various
ferroelectric distortions {\lambda} ({\lambda}=0,0.5,1.0,1.25,1.5) allows to
change the thermoelectric properties to a large extent. The polar structure
with a high polarization mode ({\lambda}=1.5) tends to show a higher TE
efficiency than the cubic structure at high temperatures. Thus, polarization
engineering may play a key role in designing efficient thermoelectric devices.
In particular, high TE performances could be achieved by growing epitaxial GeTe
films that bi-axially compress the directions perpendicular to the polar axis,
which may help to tune the Curie temperature.
