Electric field control of spin transport
S. Sahoo, T. Kontos1, J. Furer, C. Hoffmann2, M. Gräber, A. Cottet, and C. Schönenberger
Institut für Physik, Universität Basel, Klingelbergstr. 82, CH-4056 Basel, Switzerland
1 current address: Ecole Normale Supérieure; 24, rue Lhomond; F-75231 Paris Cedex 05, France
2 current address: CNRS / CRTBT; 25, Avenue des Martyrs; F-38042 Grenoble Cedex 09; France
Nature Physics 1, 99-102 (2005)
Text for a general reader
The circuits of present day electronics are based on transistors. A transistor is an electrical switch that can be turned on or off on demand via a gate electrode. Transistors steer the electric currents through a complex network converting input signals into a desired output signal, thereby performing a logic function. The signals are plain electrical currents made from a large number of mobile electrons, each carrying a unit of charge. This is similar to a water stream which is composed of water molecules, each carrying a unit of mass. However, the electron carries is in addition a magnetic information with it, which can be viewed as a tiny compass needle attached to each electron. Scientists use the term “spin” to refer to this compass needle. There is great hope for a quantum leap in electronics, if transistors can make clever use of the spin of the electron in addition to its charge. There are ideas for spin memories and spin switches alike and there are visionary concepts, in which even single spins are used as the information entity (quantum bit). In our work, we demonstrate that the spin-dependent part of the electrical current can be controlled by a gate electrode. This important finding brings the emerging field of spintronics a big step forward.
Spintronics is an approach to electronics in which the spin of the electrons is exploited to control the electric resistance R of devices. One basic building block is the spin-valve, which is formed if two...