In a Seebeck coefficient measurement, temperature and potential differences are applied so that the electric current through the setup cancels. Even though the total current vanishes, local electric currents can still flow inside the setup. This effect is also present at the nanoscale, and in single molecule junctions, the effect gives rise to a variety of current patterns. We present a mathematical tool, which can predict some of these patterns and explain different properties of the local currents.

When two spins are placed in a metal, they couple via the well-known RKKY interaction. If the metal carries an electric current, the dynamics of the two spins will be affected. We present the equations of motion for two spins in a current-carrying free-electron metal: the current gives rise to two “new” torques. Considering the result to be general, we analyze the equations and show that the new torques can drive the spin system into unexpected configurations, such as pointing anti-parallel to the magnetic field. This suggests that an electric current can be used to prepare a two-spin system in different configurations