Control of spin configuration in semiconductor artificial molecules by spin field effect transistors

The spin configuration of semiconductor artificial molecules consisting of quantum dots and spin field effect transistors (spin-FET) is studied theoretically. We find that the antiferromagnetic spin configuration can be changed to the ferromagnetic one by spin-FET. We show that the square-norm of the total spin of an artificial molecule oscillates with the rotation angle θ and has maxima at θ equal to an odd integer times π.