Researchers report room-temperature silicon spintronics

LONDON — A research team from the University of Twente (Enschede, The Netherlands) are claiming they can control a silicon electron's spin at room temperature. The researchers have published a paper to that effect in the edition of Nature published Thursday (Nov. 26).

Digital electronics is almost universally based on the detection and control of the movement of electrons through the electrical charge associated with them. However electrons also have the property of spin and transistors that function by controlling an electron's spin orientation, instead of its charge, would use less energy, generate less heat and operate at higher speeds. That theory has resulted in a field of research called spintronics. However, until now this has required low temperatures for operation.

Indeed, as the University of Twente authors comment, the ability to detect spin polarization in otherwise non-magnetic semiconductors — including gallium arsenide and silicon — using all-electrical structures has only been achieved at temperatures below 150 K and in n-type materials, which has limited further development.

The authors state that they have demonstrated room-temperature electrical injection of spin polarization into n-type and p-type silicon from a ferromagnetic tunnel contact, spin manipulation using the Hanle effect and the electrical detection of the induced spin accumulation.

The spin splitting has a life time of greater than 140-ps for conduction electrons in heavily doped n-type silicon at 300 K and greater than 270-ps for holes in heavily doped p-type silicon at the same temperature.

Nonetheless, the results open up the possibility of embedding spintronic operation in complementary silicon operating at ambient temperature.