Detecting spin-polarized currents in ballistic nanostructures.
We demonstrate a mesoscopic spin polarizer/analyzer system that allows the spin polarization of current from a quantum point contact in a large in-plane magnetic field to be measured. A transverse electron focusing geometry is used to couple current from an emitter point contact into a collector point contact. At large in-plane fields, with the point contacts biased to transmit only a single spin (g<e(2)/h), the voltage across the collector depends on the spin polarization of the current incident on it. Spin polarizations of >70% are found for both emitter and collector at 300 mK and 7 T in-plane field.
Potok
R M
RM
Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA.
Folk
J A
JA
Marcus
C M
CM
Umansky
V
V