Controlling Spin Flow
through a Single Electron Transistor with the Kondo Effect
M. Kastner

The figures show the differential conductance resulting from the Kondo effect in a single electron transistor (SET). An unpaired electron in the quantum dot inside the SET forms a weak chemical bond with electrons in the leads. A magnetic field breaks this bond between 0 and 4T, splitting the Kondo peak. At a higher field 14T one has a sharp threshold—for electrons with low energy near V_ds= 0 only one spin direction can pass through the SET.

At higher energies, electrons with opposite spin can pass too. This effect may be useful in controlling electron spins for quantum computing.