  Thermoelectric measurement of the dimensionless zT parameter requires
multiple physical quantities to be measured, therefore there is great interest
to find an experimental setup capable of measuring all these properties at
once. Previous works on impedance spectroscopy have shown promising results in
this direction, however, this technique does not lead to a complete
characterization of the thermoelectric system without additional measurement.
In order to extend impedance spectroscopy, we have investigated the measurement
of the non-linear harmonic response of a Peltier device. The experiments are
analyzed using an analytic model obtained by solving the heat equation in the
frequency regime. Our work shows that fitting the experimental response of the
system in the harmonic regime can lead to a complete characterization of the
thermoelectric properties without the need of additional measurement.
