Spin Transport Goes Ballistic

Spin Transport Goes Ballistic

The circuits in today’s computers, cell-phone cameras, and many other electronic devices rely on the manipulation of electronic charges via CMOS technology—transistors built from a combination of “complementary” metal, oxide, and semiconductor materials. A promising “beyond-CMOS” technology [1] is spintronics, in which information is carried by spin instead of charge. Spintronics devices could ...

Ballistic spin transport in exciton gases

Ballistic spin transport without net charge transport in quantum wells

We demonstrate the ballistic transport of electron spin in the absence of net transport of electron charge. Spin-up electrons move in one direction, while an equal number of spin-down electrons move with the same velocities in the opposite direction, yielding no net charge motion. This effect, also referred to as a ‘pure’ spin current, results from the quantum mechanical interference of the tra...

Ballistic Transport in Spin Field-Effect Transistors Built on Silicon

The spin field-effect transistor (SpinFET) proposed by Datta and Das [1] is composed of ferromagnetic metallic source and drain contacts which sandwich a semiconductor region. Current modulation in the devices is achieved through manipulation of the orientation of the electron spin in the semiconductor channel. We consider the value of the conduction band mismatch between the contacts and the c...

Multi-terminal spin-dependent transport in ballistic carbon nanotubes

We study theoretically non-local spin-transport in a ballistic carbon nanotube contacted to two ferromagnetic leads and two normal metal leads. When the magnetizations of the two ferromagnets are changed from a parallel to an antiparallel configuration, the circuit shows an hysteretic behavior which is specific to the few-channels regime. In the coherent limit, the amplitude of the magnetic sig...