Seebeck and Peltier effect vs Thomson effect - conductors difference

Both Seebeck effect and Peltier effect we have the need of two dissimilar conductors to break the symmetry of the system to produce a current. But, why in the Thomson effect we just need one conductor, that is, a homogeneous conductor? Shouldn't there be a balance of charges as well? What is the big difference between these effects? And, it seems that in the Thomson effect we need to have a temperature gradient and a current flow at the same time, so, it is possible generate an electric current through Thomson effect? I would really appreciate if someone could answer these questions for me.

• Mar 2 at 23:27

Similarly for the Thomson effect, which, as you point out, requires both an electric current and a thermal gradient to exist. It is a heat released/absorbed at every single point in the material where both $$I$$ and $$\nabla T$$ exist. It does not create a current per se. You actually need to input a current for it to exist.
If you want an electric current, you need the quantity $$\vec J_e =-\sigma \nabla \overline{\mu}-\sigma S \nabla T$$ not to vanish. $$\mu$$ is the electrochemical potential which generally reduces to $$eV$$, i.e. a quantity proportional to the electrostatic potential (from which you derive the voltage across 2 points).