In some metals such as Platinum Seebeck coefficient is taking for 0 conditionally. https://en.wikipedia.org/wiki/Seebeck_coefficient#Seebeck_coefficients_for_some_common_materials Or graphite. How it is possible to explain it physically? Why exactly it is "0"?
The Seebeck coeﬃcient of pristine graphite is nearly zero, because the number of electrons and the number of holes are almost equal. https://www.jim.or.jp/journal/e/pdf3/50/07/1607.pdf
I wanted to receive an explanation in terms of a charge carriers behavior. Some sources claim that in materials with zero Seebeck coefficient both electrons and holes are equally mobile and when you heat one end of the metal rod an equal amount of electrons and holes flow to the cold end. What I wish to know whether electrons and holes recombine at the cold end. If yes, does it mean such thing as carriers recombination can happen in metals?