# Kubo formula for thermopower (Seebeck coefficient)

1. Oct 17, 2015

### lyuchn

I have a long-standing puzzle about the Kubo formula of thermopower S=L_{21}/L_{11}.

The electric conductivity (L_{11}) can be expressed in terms of real time current-current correlations.
Similarly, the heat conductivity can be expressed in terms of real time correlations
of heat currents.

So how to relate thermopower, which measures the electric current driven by a temperature gradient, to some kind of current-current correlation. Here it should be the correlation between heat current and electric current. But how to derive this formula for L_{21}?
Can we simply take the gradient of 1/T as an external force? Why this holds?

2. Oct 22, 2015

### Greg Bernhardt

Thanks for the post! This is an automated courtesy bump. Sorry you aren't generating responses at the moment. Do you have any further information, come to any new conclusions or is it possible to reword the post?

3. Oct 23, 2015

### DrDu

Did you have a look at Landau Lifshitz? Would be my best guess to find something.