On the Mott formula for the thermopower of non-interacting electrons in quantum point contacts

We calculate the linear response thermopower S of a quantum point contact using the Landauer formula and therefore assume non-interacting electrons. The purpose of the paper is to compare analytically and numerically the linear thermopower S of non-interacting electrons to the low-temperature approximation, S-(1) = (pi(2)/3e)k(B)(2)T partial derivative(mu)[In G(mu T = 0)], and the so-called Mott expression, S-M = (pi(2)/3e)k(B)(2)T partial derivative(mu)[In G (mu, T)], where G (mu, T) is the (temperature-dependent) conductance. This comparison is important, since the Mott formula is often used to detect deviations from single-particle behaviour in the thermopower of a point contact.