Supercurrent-Induced Charge Imbalance Measured in a Superconductor in the Presence of a Thermal Gradient

A pair-quasiparticle potential difference arising from a quasiparticle charge imbalance has been observed in superconducting tin films along which there exist both a supercurrent, $I$, and a temperature gradient, $\nabla T$. The voltage is proportional to $I\nabla T$ at a given temperature, in agreement with the prediction of Pethick and Smith, and diverges as ${(1-\frac{T}{T_c})}^{-1\mathrm{}}$ for given values of $I$ and $\nabla T$.