Detecting spin-polarized currents in ballistic nanostructures

Phys Rev Lett. 2002 Dec 23;89(26):266602. doi: 10.1103/PhysRevLett.89.266602. Epub 2002 Dec 9.

Abstract

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.